The Devil’s Lawsuit

There was a contruction worker who was working on a building when he fell 15 stories to his bloody death. He arrived at the pearly gates and St. Peter said “Oh, I am sorry, my son. But you have been sentenced to hell.” The worker agreed – not like he could do anything else – and he was on his way. When he arrived, the devil looked at him and said, “Ah! A new slave. We shall burn you and throw you in the fiery pits.” Then the worker replied, “That wall could use a bit of patching. I could fix it first and you could throw me in the pit afterward.” So he fixed the wall. Satan, intrigued, asked, “What else can you build?” So the construction worker went about his job and made many improvements; in fact, by the time he was done, hell was a paradise. It had air conditioning, pools, balconies, you name it. Within a few days, God phoned Satan and said, “I think there has been a mix-up. That worker was originally supposed to come to heaven.” Satan replied, “No way — he’s built all sorts of useful stuff for us. We’re keeping him.” God then said, “Oh, yeah? Well, I’ll see you in court. We’re going to sue you for this man’s soul and damages.” Satan just laughed: “And where are you going to find a lawyer?”

Bob was in trouble. He forgot his wedding anniversary. His wife was really pissed. She told him “Tomorrow morning, I expect to find a gift in the driveway that goes from 0 to 200 in 6 seconds AND IT BETTER BE THERE !!” The next morning he got up early and left for work. When his wife woke up, she looked out the window and sure enough there was a box gift-wrapped in the middle of the driveway. Confused, the wife put on her robe and ran out to the driveway, brought the box back in the house. She opened it and found a brand new bathroom scale.

 

Bob has been missing since Friday.

A local United Way office realized that the organization had never received a donation from the town’s most successful lawyer. The person in charge of contributions called him to persuade him to contribute. “Our research shows that out of a yearly income of at least $500,000, you give not a penny to charity. Wouldn’t you like to give back to the community in some way?” The lawyer mulled this over for a moment and replied, “First, did your research also show that my mother is dying after a long illness, and has medical bills that are several times her annual income?” Embarrassed, the United Way rep mumbled, “Um … no.” The lawyer interrupts, “or that my brother, a disabled veteran, is blind and confined to a wheelchair?” The stricken United Way rep began to stammer out an apology, but was interrupted again. “or that my sister’s husband died in a traffic accident,” the lawyer’s voice rising in indignation, “leaving her penniless with three children?!” The humiliated United Way rep, completely beaten, said simply, “I had no idea…” On a roll, the lawyer cut him off once again, “So if I don’t give any money to them, why should I give any to you?”

A blonde, wanting to earn some money, decided to hire herself out as a handyman-type and started canvassing a wealthy neighborhood. She went to the front door of the first house and asked the owner if he had any jobs for her to do. “Well, you can paint my porch. How much will you charge?” The blonde said, “How about 50 dollars?” The man agreed and told her that the paint and ladders that she might need were in the garage. The man’s wife, inside the house, heard the conversation and said to her husband, “Does she realize that the porch goes all the way around the house?” The man replied, “She should. She was standing on the porch.” A short time later, the blonde came to the door to collect her money. “You’re finished already?” he asked. “Yes,” the blonde answered, “and I had paint left over, so I gave it two coats. “Impressed, the man reached in his pocket for the $50. “And by the way,” the blonde added, “that’s not a Porch, it’s a Ferrari.”

There are two days in every week about which we should not worry,
two days which should be kept free from fear and apprehension.

One of these days is Yesterday with all its mistakes and cares,
its faults and blunders, its aches and pains.

Yesterday has passed forever beyond our control.
All the money in the world cannot bring back Yesterday.

We cannot undo a single act we performed;
we cannot erase a single word we said.
Yesterday is gone forever.

The other day we should not worry about is Tomorrow
with all its possible adversities, its burdens,
its large promise and its poor performance;
Tomorrow is also beyond our immediate control.

Tomorrow’s sun will rise,
either in splendor or behind a mask of clouds, but it will rise.
Until it does, we have no stake in Tomorrow,
for it is yet to be born.

This leaves only one day, Today.
Any person can fight the battle of just one day.
It is when you and I add the burdens of those two awful eternities
Yesterday and Tomorrow that we break down.

It is not the experience of Today that drives a person mad,
it is the remorse or bitterness of something which happened Yesterday and the dread of what Tomorrow may bring.

Let us, therefore, Live but one day at a time.

A man stopped at a flower shop to order some flowers to be wired to his mother who lived two hundred miles away

As he got out of his car he noticed a young girl sitting on the curb sobbing.

He asked her what was wrong and she replied, “I wanted to buy a red rose for my mother. But I only have seventy-five cents, and a rose costs two dollars.”

The man smiled and said, “Come on in with me. I’ll buy you a rose.”

He bought the little girl her rose and ordered his own mother’s flowers.

As they were leaving he offered the girl a ride home. She said, “Yes, please! You can take me to my mother.”

She directed him to a cemetery, where she placed the rose on a freshly dug grave.

The man returned to the flower shop, canceled the wire order, picked up a bouquet and drove the two hundred miles to his mother’s house.

Rainwater harvesting – an HIA of
rainwater harvesting in the UK

3.1 INTRODUCTION
Rainwater harvesting is a very simple concept, where rain falling onto a roof surface is collected and subsequently used as a source of water. It has been in use in some areas (e.g. Israel, Africa and India) probably since 2000 BC and is now used in both developing and developed countries where it provides both potable (e.g. Australia, Canada, USA) and non-potable supplies (e.g. Germany).
As the predicted use of rainwater harvesting in the UK is for domestic non- potable use (i.e., toilet flushing, laundry use, garden watering etc.) most of the discussion here is related to non-potable supplies, although experience from potable systems is drawn upon in assessing possible health effects (through inadvertent or deliberate consumption of harvested rainwater).
© 2008 IWA Publishing. Health Impact Assessment for Sustainable Water Management. Edited by
Lorna Fewtrell and David Kay. ISBN: 9781843391333. Published by IWA Publishing, London, UK.

The simplest rainwater collection method, and the one with the longest history in the UK, is the garden water butt. More complex constructed household rainwater harvesting systems can, however, increase the amount of water ‘saved’. They are probably most easily accommodated into new build designs. In the UK, in-house systems typically consist of an underground storage tank, a filter to prevent the entry of leaves and large solids, a smoothing inlet to stop sediment on the bottom of the tank being disturbed, a pump for distributing the harvested water (either to a header tank or directly to appliances) and a suction filter to prevent the uptake of any floating material as the water is drawn up for use. Systems also have an automatic mains top-up device which, depending upon the system, may supply the storage tank, a header tank or the actual appliances with mains water if harvested supplies run short.
3.2 RISK ASSESSMENT
For the purposes of this health impacts examination the following scenario has been considered:
• Each property has a household rainwater system, with an underground tank (such as that shown in Plate 3.1), collecting rainwater from the roof via downpipes, passing through a filter on entry to the tank. The tank receives top up supplies from the mains water when it is running low and the supplies are used for toilet flushing and garden watering. The system operation and its maintenance are the responsibility of the individual householder.
3.2.1 Possible hazards associated with rainwater harvesting
A health hazard is anything that can potentially cause harm (with harm being loss of life, injury, illness and so on). The following hazards have been identified:
• drowning and near-drowning;
• injury; and
• infection.
3.2.2 Exposure assessment
The HIA was conducted on a hypothetical population based on a newly built estate in the South of England, as outlined in Chapter 2 (section 2.5).

Plate 3.1. Typical tank design (Photo: L. Fewtrell)
3.2.2.1 Drowning and near-drowning
This will, to some degree, depend upon the type of tanks used. In some countries, Australia for example, above ground rainwater harvesting tanks are common (Cunliffe 1998). In the UK, however, tanks tend to be underground. All such tanks have manhole covers and some prevent actual access to the water by the positioning of the filter (Plate 3.2). Thus, it has been assumed that there can be no exposure and hence no risk of drowning.
3.2.2.2 Injury
The scope for injury is determined by user behaviour during maintenance, especially during gutter clearing and tank inspection and cleaning. The former would require ladder access and the latter may present a confined space access risk. There is also the possibility that the manhole cover could be removed during inspection or left unsecured following inspection.
Falls are the most common cause of both fatal and nonfatal unintentional injury (accidents) in the home environment (Dowswell et al. 1999; Marshall et al. 2005). An important component of this statistic is made up by falls from

Plate 3.2. Manhole access showing filter (Photo: L. Fewtrell)
ladders (and scaffold), usually as a result of incorrect ladder placement or from excessive reaching (Partridge et al. 1998). Examining the risk of injury per hour of exposure to various consumer products, Hayward (1996) found that ladders and scaffolding rated highly, with between 10 and 65 accidents per million hours of use (with scaffold being second in the list, behind electric hedge-trimmers). Ladders and scaffolding were also among the products associated with the longest mean duration of incapacity, with an average incapacity per accident of 18.8 days (Hayward 1996).
In Australia, a study looking at the nature, severity and outcome of injuries sustained from ladder falls found that 83% of those presenting in hospital as a result of a ladder fall were male and that 78% were injured in a non-occupational setting (Tsipouras et al. 2001). Over 40% of the accidents were caused by ladder instability. Most of the patients had mild or moderate injuries, but 13% had severe trauma, usually with head, chest or spinal injury. In Denmark, a similar study found that the mean annual rate of ladder falls was 1.18 per 1,000 in males and 0.41/1,000 in females (Faergemann and Larsen 2000). A rise in the annual incidence rates for both men and women was seen with increasing age. About 20% of injuries resulted in hospitalisation for a median of seven days. 50% of

the injuries were contusions (bruises) or sprains and about 30% were fractures or dislocations.
In the UK, good surveillance data are available relating to falls including those from ladders. In 1994 and 1995, 73 and 67 people respectively were killed as a result of falling from a ladder or scaffolding in England and Wales. Of these fatalities over 50% occurred at home (as opposed to being occupational injuries) and the percentage of home fatalities was found to increase by age (Dowswell et al. 1999). The Home Accident Surveillance System (HASS) maintained by RoSPA is a UK database holding details of home accidents (up to 2002) that were serious enough to warrant a visit to hospital. Data are derived from a sample of admissions to between 16 and 18 hospital accident and emergency departments in the UK, and national estimates are made based on this sample. The data for falls on/from ladders/stepladders for 2000 to 2002 are shown in Table 3.1.
Table 3.1. Incidents involving falls from or onto ladders and stepladders in the home 2000 to 2002 (DTI 2003)
Number of incidents

Year Sample data National estimate Multiplier*
2000 1816 32,216 17.64
2001 1903 33,969 17.85
2002 1721 35,281 20.50

* The multiplier was not given in the report, but was calculated from the national estimate and sample data for each year.
Examination of data for 2000 to 2002 revealed 187 incidents involving the use of ladders to access gutters (135 of these were specifically related to cleaning gutters). Using an average of the multipliers (Table 3.1) this suggests that on average 840 people each year will injure themselves cleaning their gutters. As only one of the patients was under the age of 16, the incidence has been calculated based on the adult population (48,047,425 – National Statistics 2005), giving an incidence rate of 0.0 17/1000 population. From the annual incidence rate it is estimated that 0.062 people per year at the case study site will injure themselves as a result of examining or cleaning their guttering. It has been assumed that householders are aware of their rainwater harvesting system and a proportion of them may clean their gutters more frequently than before as a result of perceived maintenance needs. Thus 20% of incidents have been attributed to rainwater harvesting, resulting in an estimate of 0.0 12 people sustaining injuries.

Confined space qualitative estimate
A confined space is any space of a substantially closed nature where there is a risk of death or serious injury from hazardous substances or dangerous conditions (e.g. lack of oxygen). Some confined spaces are fairly easy to identify; enclosures with limited openings, such as an underground rainwater harvesting tank (HSE 1997). Data on morbidity and mortality relating to exposure to confined spaces in non-occupational circumstances are not readily available. It is likely that incidents relating to confined spaces (including those arising from occupational exposure) would be coded as W811 (confined to or trapped in a low-oxygen environment) or W84 (unspecified threat to breathing). During the three year period (2001 – 2003) there were three deaths coded as W81 in England and Wales and 99 coded as W84 (National Statistics 2001, 2002, 2003), representing annual incidence rates of 0.018/million population and 0.62/million population respectively. Neither of these codes, however, is very specific (e.g., W81 includes ‘accidentally shut in refrigerator or other airtight spaces, diving with insufficient air supply’ – WHO 2003). The type of tank in the case study is designed to prevent entry (Plate 3.2), so it has been assumed that there is no risk of confined space entry. As with some tank designs, however, entry may be possible a qualitative estimate of (—) has been given to this hazard.
3.2.2.3 Infection
Infection relating to rainwater harvesting could occur via a number of routes, namely:
• Inappropriate ingestion/contact: through ingestion of aerosols produced as a result of toilet flushing; direct ingestion via the garden tap; direct contact through using the garden tap to fill up paddling pools, hot tubs, swimming pools etc., inadvertent ingestion/contact through contamina-tion of drinking-water supplies as a result of cross connections.
• Inhalation of microorganisms within an aerosol: via toilet flushing.
• Microbial contamination of the environment: and subsequent ingestion of garden produce contaminated as a result of watering with rainwater.
• Vector-borne illness: stored water could become a breeding site for mosquitoes.
1 i.e. according to the International Classification of Disease, version 10 (WHO 2003)

The principal pathogen source in harvested rainwater in the UK is likely to be from bird faeces. From an examination of the literature it is clear that a number of different bird species carry a variety of human pathogens, which could be deposited on roofs and washed off into harvested rainwater supplies. The two most commonly studied are Salmonella spp. and Campylobacter spp. (typically Campylobacterjejuni). A recent review (Fewtrell and Kay 2007) suggested that a number of human enteric pathogens have been isolated from rainwater supplies; including Campylobacter spp., Salmonella spp., Cryptosporidium spp. and Giardia spp. Campylobacter spp. and Cryptosporidium spp. were chosen here to quantify the risks of infection. While it is acknowledged that other pathogens may be present in the water the choice of these pathogens is generally conservative (with Campylobacter having a lower infectious dose than Salmonella, and Cryptosporidium having a similar infectious dose to Giardia) and the risk from these pathogens was felt to be indicative of infection risk with bacterial and protozoan pathogens.
The following possibilities of infection were examined:
• ingestion of Campylobacter spp. from aerosol formed during toilet flushing;
• ingestion of Campylobacter spp. and Cryptosporidium spp. due to direct ingestion of harvested rainwater or through contamination of drinking water supplies via cross connections; and
• ingestion of garden produce contaminated with Cryptosporidium spp.
3.2.2.3.1 Campylobacter spp.
Campylobacter spp. is a bacterial pathogen capable of causing human infection, which is commonly carried by birds such as blackbirds, starlings and gulls (Moore et al. 2002; Waldenstrom et al. 2002; Broman et al. 2002) and has been detected in harvested rainwater supplies (Savill et al. 2001; Albrechtsen 2002). Campylobacter is the most commonly reported bacterial cause of infectious intestinal disease (gastroenteritis) in England and Wales (HPA 2005). The illness, campylobacteriosis, is characterized by severe diarrhoea and abdominal pain. In some cases chronic sequela (secondary adverse health outcomes), such as Guillain-Barré syndrome, may occur as a result of Campylobacter infection (Mead et al. 1999).
Dose-response is the quantitative relationship between dose and outcome (e.g. ID50 is the number of microbes required to initiate infection in 50% of the exposed population). A dose-response (3-poisson) model for Campylobacter spp. has been developed by Medema et al. (1996), based on the experimental

data reported by Black et al. (1988). A duration of 6 days, with a severity weight of 0.086 has been assumed for uncomplicated campylobacteriosis (based on a weight of 0.067 for the majority of cases and 0.39 for the 6% of cases expected to visit their general practitioner). Where there are complications a severity weight of 0.28, with a duration of 365 days has been assumed (adapted from Havelaar et al. 2000). A total of 30% of infections are assumed to cause clinical illness and 0.5% of clinical illness is considered to be severe or complicated (based on the rate for campylobacteriosis hospitalisation cited by Mead et al. 1999). The case fatality rate for campylobacteriosis is 0.005% (Mead et al. 1999), with a median age at death of 78 years (Havelaar et al. 2000).
Exposure to Campylobacter spp. through toilet flushing
The data required to estimate the exposure of the case study population to Campylobacter through the use of harvested rainwater supplies for toilet flushing are shown in Table 3.2.
It has also been assumed that each day has the same likelihood of Campylobacter contamination and that the microorganisms are suspended homogenously in water.
Exposure to Campylobacter spp. through direct ingestion (external tap use)
It has been assumed that during the summer months, and in particular the six week school holiday period, some children may drink water from the garden tap (supplied by harvested rainwater). This assumes that any signs relating to the water not being for drinking are ignored and there is access to the taps. It has also been assumed that children under the age of 5 are either supervised or could not turn on the tap. The data requirements for this analysis are shown in Table 3.3.
Exposure to Campylobacter spp. through cross connections (contaminated potable supplies)
There are no data on the number of cross connections that result from having a dual supply (potable and non-potable) system within the household in the UK. It has, however, been seen in other countries in relation to large scale recycling schemes (e.g. Murray 2005). Thus, it remains a possibility, despite the best efforts of system installation engineers and designers to clearly differentiate between the systems on the basis of pipe colour, dimensions and incompatible fittings. The data requirements for this analysis are shown in Table 3.4.

Table 3.2. Exposure to Campylobacter spp. through toilet flushing
Data requirements Comments

The concentration of Campylobacter in the harvested rainwater
The frequency of contamination of rainwater supplies with Campylobacter spp.
The fraction of these organisms capable of initiating infection

Very few studies have attempted to quantify levels of Campylobacter spp. in harvested rainwater (presence/absence data only). Savill et al. (2001), however, did quantify levels and found a maximum concentration of 0.56 MPN/100ml.
Albrechtsen (2002) reported Campylobacter spp. in 20% of samples, while Holländer et al. (1996) did not detect it in over 140 samples analysed. For this analysis it has been assumed to occur between 0 and 10% of the time (with no allowance made for seasonal variation).
Dose-response model of Medema et al. (1996), where a=0.145 and 3=7.59

Amount of water swallowed Flushing a toilet produces an aerosol. The volume
of water ejected during a ‘typical’ flush is unknown but is likely to be small and probably between 1 and 2ml. Only a proportion (say a tenth) of this is likely to reach a susceptible host.
Number of flushes per day Frequency of toilet use is assumed to be between
3 and 6 times/day, with the range accounting for home workers and those who work away from home (MTP 2006). Children under the age of 3 are not thought to be exposed as they are unlikely to be toilet trained (AAP 2000).
The frequency with which people are exposed to contaminated flush water It has been assumed that people will be exposed to aerosol 5% of the time (1 flush in 20)

3.2.2.3.2 Cryptosporidium spp.
Cryptosporidium spp. is a protozoan pathogen capable of causing human infection. Cryptosporidiosis commonly produces self-limiting diarrhoea which can sometimes include nausea, vomiting and fever. Although it usually resolves within a week in otherwise healthy people, it can last for a month or more. The severity of illness depends on age and immune status; infections in immunocompromised people can be severe and even life-threatening. The most

Table 3.3. Exposure to Campylobacter spp. through direct ingestion (external tap use)
Data requirements Comments

The level of contamination with Campylobacter spp.
The frequency of contamination of rainwater supplies with Campylobacter spp.
The fraction of these organisms capable of initiating infection
The amount of un-boiled water consumed
The number of children likely to drink from external taps See Table 3.2
See Table 3.2
See Table 3.2
A UK report on water consumption (MEL 1996) reported that the average amount of tap water consumed daily was 1 138ml of which un-boiled water accounted for 16.7% (or 190ml)
It has been assumed that during the 6 week summer holiday period between 0 and 5% of children aged between 5 and 14 drink from the outside tap on an occasional basis (between 0.5 and 2 times a week) and consume between 50 and 250ml on each occasion

Table 3.4. Exposure to Campylobacter spp. through cross connections
Data requirements Comments

The likely number of households to be affected by cross connections, and the duration of the problem
The level of contamination with Campylobacter spp.
The frequency of contamination of rainwater supplies with
Campylobacter spp.
The fraction of these organisms capable of initiating infection
The amount of un-boiled water consumed
It has been assumed that between 0 and
0.1% of households are affected each
year and that the problem lasts for
between 10 and 60 days. Other house-
holds are assumed not to be affected.
0.28 MPN/100ml based on a 50% reduction in the concentration reported by Savill et al. 2001 (see Table 3.2) to account for the dilution effect of the drinking water supply
See Table 3.2
See Table 3.2
See Table 3.3

commonly used dose-response relationship is an exponential model (Teunis et al. 1996; WHO 2002) based on data from DuPont et al. 1995. A duration of 6 days, with a severity weight of 0.054 has been assumed for the immunocompetent (‘normal’) population (with 71% of infections progressing to illness), while a duration of 47 days and a severity weighting of 0.13 has been assumed for AIDS patients, where all infection progresses to illness (Havelaar et al. 2000). As almost 90% of the case study population classified their health as good, a rate of 0.05% HIV/AIDS prevalence has been assumed, rather than the estimated UK national level of 0.2% (CIA 2005).
Exposure to Cryptosporidium spp. through direct ingestion (external tap use)
Many of the data requirements are the same as those for Campylobacter spp. detailed above. The data requirements are outlined in Table 3.5.
Table 3.5. Exposure to Cryptosporidium spp. through direct ingestion (external tap use)
Data requirements Comments

The concentration of Cryptosporidium in the harvested rainwater
The frequency of contamination of rainwater supplies with Cryptosporidium spp.
The fraction of these organisms capable of initiating infection
The amount of un-boiled water consumed
The number of children likely to drink from external taps

Albrechtsen (2002) reported Cryptosporidium concentrations ranging between 0 and 50/l
0–10% – as for Campylobacter
Dose-response model of Teunis et al.
(1996) applies, where r 1/4 0.004
See Table 3.3
See Table 3.3

Exposure to Cryptosporidium spp. through cross connections (contaminated potable supplies)
The requirements to determine the risk from exposure to Cryptosporidium spp. as a result of cross connections are shown in Table 3.6.

Table 3.6. Exposure to Cryptosporidium spp. through cross connections
Data requirements Comments
The likely number of households to be See Table 3.4
affected by cross connections
The level of contamination with Cryptosporidium spp.
The frequency of contamination of rainwater supplies with
Cryptosporidium spp.
The fraction of these organisms capable of initiating infection As Table 3.5, but by reduced by 50% to account for dilution by drinking water supply
See Table 3.5
See Table 3.5

The amount of un-boiled water consumed See Table 3.4
Exposure to Cryptosporidium spp. through contaminated garden produce
It has been assumed that people in the case study population growing their own fruit and vegetables will water their produce using rainwater supplies, which could on occasion be contaminated with Cryptosporidium spp. The products considered to present the greatest risk are salad plants, as the food part of the plant (which is subsequently eaten raw) will be watered directly and, in addition to possible root uptake, may retain any contamination (at least for a period of time). Data requirements for this analysis are outlined in Table 3.7.
No account has been taken of pathogen removal with washing, or of people other than the householders who are growing the produce eating contaminated salad crops (i.e. no assessment of risks from householders who give away some of their produce has been made).
3.2.2.3.3 Other infections and qualitative estimates
Inhalation of microorganisms via aerosols, contact and dermal exposure to rainwater supplies and vector-borne illness were not subject to quantitative microbial risk assessment. Legionella pneumophila would be expected to be the principal pathogen of concern in aerosol inhalation, however, this is rarely found in rainwater samples in Europe (e.g. Holländer et al. 1996; Albrechtsen 2002; Birks et al. 2004) and is unlikely to multiply at the temperatures recorded in underground tanks. Thus this hazard has been given an estimate of (—).
Although there is a possibility that people could be exposed to Pseudomonas aeruginosa via rainwater supplies (Holländer et al. 1996; Albrechtsen 2002), this is an opportunistic pathogen (Hardalo and Edberg 1997) which only

Table 3.7. Exposure to Cryptosporidium spp. through consumption of contaminated garden produce
Data requirements Comments
The level of contamination with See Table 3.5
Cryptosporidium spp.

See Table 3.5
See Table 3.5
A MORI poll, commissioned by the Royal Horticultural Society estimated that 41% of people grow their own fruit and vegetables (410/1000) and that over a 2-year period 12% of these have attempted to grow lettuce (MORI 2004; RHS 2004). Thus is has been assumed that each year 6% of the fruit and vegetable growing population grow lettuce (i.e. 25/1000). This figure has been applied on a household basis to the study population.
Figures from Northern Ireland (NFS 2005) suggest an average weekly lettuce (and leafy salad) consumption of 25.9 g/person. It has been assumed that families who grow their own vegetables will eat double this amount of their own produce between June and October (i.e. a five month season).
It is assumed that any contamination resulting from watering in the final week of growth will remain on the produce during harvesting

occasionally causes skin problems in healthy people (usually in association with hot tubs or similar facilities – Rasmussen and Graves 1982; CDC 2000) and has, thus, been given a qualitative estimate of (—).
It is unlikely that nutrient levels within an underground rainwater tank would be adequate for the development of mosquito larvae; therefore rainwater harvesting systems are unlikely to play a role in vector-borne disease.
3.2.3 Risk characterization
The estimates relating to injury are determined by multiplying the number of
occurrences by the severity weight and duration to calculate the years lived with

a disability. Where an occurrence is fatal it has been assumed to occur at the age of eight in children and 45 in adults (unless otherwise noted). The years of life lost are calculated by subtracting the age of death from the UK average (79 based on rounded figures of 77 in men and 81 in women – GAD 2007).
3.2.3.1 Injury
The analysis of exposure (3.2.2.2) estimated that 0.012 people would be injured on an annual basis as a result of cleaning their gutters to maintain their rainwater harvesting system. It has been assumed that no fatalities occur, but that people suffer either from hospitalisation (20%), fractures/dislocations (20%) or bruises/ sprains (50%). Table 3.8 shows the severity weights and durations attributed to each of these outcomes (WHO 2005; Stouthard et al. 1997).
Table 3.8. Severity weights and duration of incapacitation for ladder-related injuries
Outcome Severity Duration Comments
weight (days)
Hospitalisation 0.25 120 Based on double the figures for
fractures
Fractures/dislocations 0.125 60 Severity weight based on the
average of a break of the radius, ulna, hand bones, ankle, foot bones and dislocation. Duration considered to be three months.
Bruises/sprains 0.064 14 Severity weight based on figures for
sprain
Applying these figures to the number of injuries gives a DALY score of 0.0003.
3.2.3.2 Infection
Where possible, parameters for the individual infection exposures were entered into @Risk (Palisade Corporation 2002) as probability distributions rather than point estimates, in order to examine the effects of uncertainty and the assumptions to which the estimate was most sensitive. The data for severity weights and each of the infection exposures are summarised as a series of Tables in the Appendix (Tables A3.1–A3.7).
3.2.3.3 Summary of risk characterization
Table 3.9 summarises the risk characterization for each of the identified hazards applied to the case study population.

Rainwater harvesting
Table 3.9. Risk characterization summary (rainwater harvesting) 59
Hazard Exposure Group Estimate Annual cases DALYs
Drowning All 0 0
Injury Gutter-related incident
Adults 0.012 0.0003
Confined space incident
All Qualitative (-)
Illness Campylobacteriosis from toilet flushing
All Min 3.2 x 10-5 9.7 x 10-8
Mean 0.015 4.6 x 10-5
Max 0.11 3.4 x 10-4
Campylobacteriosis from direct ingestion (external tap)
Children Min 2.2 x 10-4 6.8 x 10-8
Mean 0.006 1.8 x 10-5
Max 0.038 1.1 x 10-4
Cryptosporidiosis from direct ingestion (external tap)
Children Min 3.3 x 10-5 2.9 x 10-8
Mean 0.004 3.4 x 10-6
Max 0.035 3.1 x 10-5
Campylobacteriosis from cross connections
All Min 0 0
Mean 0.003 9.9 x 10-6
Max 0.022 6.5 x 10-5
Cryptosporidiosis from cross connections
Norm pop Min 0 0
Mean 0.002 1.9 x 10-6
Max 0.024 2.4 x 10-5
Immunocomp Min 0 0
Mean 1.4 x 10-6 2.3 x 10-8
Max 1.7 x 10-5 2.8 x 10-7
Respiratory illness via aerosol
All Qualitative (-)
Skin infection via dermal contact
All Qualitative (-)
Cryptosporidiosis from ingestion of garden produce
Norm pop Min 2.2 x 10-4 2.2 x 10-7
Mean 0.08 8.0 x 10-5
Max 0.47 4.6 x 10-4
Immunocomp Min 1.2 x 10-7 2.0 x 10-9
Mean 4.3 x 10-5 7.3 x 10-7
Max 2.5 x 10-4 4.2 x 10-6
Vector-borne illness
All 0 0

Norm pop: Normal population Immunocomp: Immunocompromised population
Min: minimum estimate Mean: mean estimate
Max: maximum estimate (-): minor health impact

Figure 3.1 shows a graphical representation of the results of the mean estimate.
Figure 3.1. Annual DALYs by possible hazard (rainwater harvesting system)
It can be seen from Figure 3.1 that injury has the greatest DALY score, followed by cryptosporidiosis from eating contaminated garden produce and campylobacteriosis from toilet flushing. This information could be used to prioritise risk management strategies, such as an estate rainwater harvesting package where an external company services the system each year, eliminating the need for households to attempt cleaning their gutters. Such a package could actually have in an additional health benefit as, presumably, it would remove the need for any householder to clean their gutters (for what ever reason), which could prevent an additional 0.05 incidents (equivalent to 0.001 DALYs).
3.3 HEALTH IMPACT STATEMENT
This brings together all of the identified health impacts summarised in Table 3.9
(mean estimates) and presents the results on the basis of an overall DALY score.
Total DALY score: 4.59 • 10—4 Qualitative estimate: 3(—)
3.4 DISCUSSION
The estimated DALY scores from both the mean estimate and the maximum
estimate fall well within the screening level and the WHO reference level of risk
outlined in Chapter 2. This is clearly shown in Figure 3.2, which compares the

annual DALY estimates and the reference levels, on a case study population basis, on a log10 scale.
Figure 3.2. Summary of DALY scores (log10 scale)
In order to conduct the HIA, it was necessary to make a number of assumptions, such as the number of people likely to be injured while cleaning their gutters. As far as possible, these were based on data in the literature. Where no data were available (such as the number of children likely to drink from an external tap) documented estimates were made which enable the assumptions to be challenged and (if appropriate) alternatives to be investigated.
For the QMRA, ranges of data were incorporated into the estimates with Monte Carlo analysis used to derive minimum and maximum values. As noted above, even the maximum estimate falls well within both reference levels of risk. It is however, possible to test further some of these assumptions by deliberately choosing elevated levels. For example, ingestion of aerosolized toilet flush water could be increased to 10ml per flush (surely a noticeable and hopefully infeasible amount) and the individual DALY score for that aspect of the assessment still falls within the reference risk levels. Similarly, if the Campylobacter spp. concentration of the toilet flush water (derived from the harvested rainwater) is increased to 100/100ml (a level not dissimilar to that seen in polluted river water), the individual DALY score reaches 3.4 • 10-6, slightly greater than the WHO reference level, but less than the screening level.
3.5 REFERENCES
AAP (2000) Age 3 to 5: Beyond toilet training. American Academy of Pediatrics. Albrechtsen, H-J. (2002) Microbiological investigations of rainwater and graywater collected for toilet flushing. Water Science and Technology 46, 311–316.

Atherton, F., Newman, C.P.S. and Casemore, D.P. (1995) An outbreak of waterborne cryptosporidiosis associated with a public water supply in the UK. Epidemiology and Infection 115, 123–131.
Birks, R., Colbourne, J., Hills, S. and Hobson, R. (2004) Microbiological water quality in a large in-building, water recycling facility. Water Science and Technology 50(2), 165–172.
Black, R.E., Levine, M.M., Clements, M.L., Hughes, T.P. and Blaser, M.J. (1988) Experimental Campylobacter jejuni infection in humans. Journal of Infectious Diseases 157(3), 472–479.
Broman, T., Palmgren, H., Bergstrom, S., Sellin, M., Waldenstrom, J., Danielsson-Tham, M-L. and Olsen, B. (2004) Campylobacter jejuni in black-headed gulls (Larus ridibundus): prevalence, genotypes and influence on C. jejuni epidemiology. Journal of Clinical Microbiology 40(12), 4594–4602.
CDC (2000) Pseudomonas dermatitis/folliculitis associated with pools and hot tubs – Colorado and Maine, 1999–2000. Morbidity and Mortality Weekly Report 49, 1087–1091.
CIA (2005) The World Fact Book 2005. Central Intelligence Agency, USA. http://
http://www.cia.gov/cia/publications/factbook/geos/uk.html accessed 07/12/05
Cunliffe, D. (1998) Guidance on the use of rainwater tanks. National Environmental
Health Forum Monographs. Water Series No. 3. Australia.
Dowswell, T., Towner, E., Cryer, C., Jarvis, S., Edwards, P. and Lowe, P. (1999) Accidental falls: fatalities and injuries. An examination of the data sources and review of the literature on preventive strategies. A report prepared for the Department of Trade and Industry URN 99/805.
DTI (2003) 24th (final) report of the home and leisure accident surveillance system. 2000, 2001 and 2002 data. Department of Trade and Industry, London.
DuPont, H.L., Chappell, C.L., Sterling, C.R., Okhuysen, P.C., Rose, J.B. and Jakubowski, W. (1995) The infectivity of Cryptosporidium parvum in healthy volunteers. New England Journal of Medicine 332(13), 855–859.
Faergemann, C. and Larsen, L.B. (2000) Non-occupational ladder and scaffold fall injuries. Accident Analysis and Prevention 32(6), 745–750.
Fewtrell, L. and Kay, D. (2007) Microbial quality of rainwater supplies in developed countries. Urban Water Journal 4(4), 253–260.
GAD (2007) Interim life tables 2003–2005. UK. Male and female. Government’s Actuary Department, UK Government, London.
Hardalo, C. and Edberg, S.C. (1997) Pseudomonas aeruginosa: assessment of risk from drinking water. Critical Reviews in Microbiology 23(1), 47–75.
Havelaar, A.H., de Witt, M.A.S., van Koningsveld, R. and van Kempen, E. (2000) Health burden in the Netherlands due to infection with thermophilic Campylobacter spp. Epidemiology and Infection 125, 505–522.
Hayward, G. (1996) Risk of injury per hour of exposure to consumer products. Accident Analysis and Prevention 28, 115–121.
Holländer, R., Bullermann, M., Groß, C., Hartung, H., Ko¨nig, K., Lu¨cke, F-K. and Nolde, E. (1996) [Microbiological and hygienic aspects of the use of rainwater as process water for toilet flushing, garden irrigation and laundering]. Gesundheitswesen 58, 288–293. [Article in German]

HPA (2005) Campylobacter. Health Protection Agency, London. http://www.hpa.org.uk/ infections/topics_az/campy/menu.htm Accessed November 2006
HSE (1997) Safe work in confined space. Health and Safety Executive, UK.
Marshall, S.W., Runyan, C.W., Yang, J., Coyne-Beasley, T., Waller, A.E., Johnson, R.M.
and Perkis, D. (2005) Prevalence of selected risk and protective factors for falls in
the home. American Journal of Preventive Medicine 28(1), 95–101.
Mead, P.S., Slutsker, L., Dietz, V., McCaig, L.F., Bresee, J.S., Shapiro, C., Griffen, P.M. and Tauxe, R.V. (1999) Food-related illness and death in the United States. Emerging Infectious Diseases 5(5), 607–625.
Medema, G.J., Teunis, P.F.M., Havelaar, A.H. and Haas, C.N. (1996) Assessment of the dose-response relationship of Campylobacter jejuni. International Journal of Food Microbiology 30, 101–111.
MEL (1996) Tap water consumption in England and Wales: findings from the 1995 national survey. MEL Research Report 9448-01.
Moore, J.E., Gilpin, D., Crothers, E., Canney, A., Kaneko, A. and Matsuda, M. (2002) Occurrence of Campylobacter spp. and Cryptosporidium spp. in seagulls (Larus spp.). Vector Borne Zoonotic Diseases 2(2), 111–114.
MORI (2004) Good Life Factor RHS. Omnibus questions – topline results. MORI/22234. http://www.chelseashow.com/publications/pubs/garden0704/morireportonline.pdf accessed 16/01/06
MTP (2006) BN DW WC: WC design and efficiency – briefing note relating to policy
scenario objectives in policy brief. Market Transformation Programme.
Murray, K. (2005) Families forced to drink effluent. Daily Telegraph, Australia January
12, 2005.
National Statistics (2001) Mortality statistics – cause. Review of the Registrar General on deaths by cause, sex and age in England and Wales, 2001. Series DH2 no. 28. Office for National Statistics, London.
National Statistics (2002) Mortality statistics – cause. Review of the Registrar General on deaths by cause, sex and age in England and Wales, 2002. Series DH2 no. 29. Office for National Statistics, London.
National Statistics (2003) Mortality statistics – cause. Review of the Registrar General on deaths by cause, sex and age in England and Wales, 2003. Series DH2 no. 30. Office for National Statistics, London.
National Statistics (2005) Population Estimates. http://www.statistics.gov.uk/cci.nugget. asp?id=6
NFS (2005) National Food Survey: Quarterly consumption of household food. Northern Ireland.
Palisade Corporation (2002) Guide to using @Risk: risk analysis and simulation add in for Microsoft Excel. Version 4.5. Palisade Corporation, Newfield, New York, USA. http://www.palisade.com
Partridge, R.A., Virk, A.S. and Antosia, R.E. (1998) Causes and patterns of injury from ladder falls. Academic Emergency Medicine 5(1), 3 1–34.
Rasmussen, J.E. and Graves, W.H. (1982) Pseudomonas aeruginosa, hot tubs, and skin infections. American Journal of Diseases of Children 136, 553–554.
RHS (2004) RHS says dig your way to health in national allotments week. Royal Horticultural Society, UK.

Savill, M.G., Hudson, J.A., Ball, A., Klena, J.D., Scholes, P., Whyte, R.J., McCormick, R.E. and Jankovic, D. (2001) Enumeration of Campylobacter in New Zealand recreational and drinking waters. Journal of Applied Microbiology 91, 38–46.
Stouthard, M., Essink-Bot, M., Bonsal, G., Barendregt, J. and Kramers, P. (1997) Disability weights for disease in the Netherlands. Rotterdam: Department of Health, Erasmus University. Cited by VGDHS (1999).
Teunis, P.F.M., van der Heijden, O.G., van der Giessen, J.W.B. and Havelaar, A.H. (1996) The dose-response relation in human volunteers for gastro-intestinal pathogens. RIVM Report 284550002, Bilthoven, Netherlands.
Tsipouras, S., Hendrie, J.M. and Silvapulle, M.J. (2001) Ladders: accidents waiting to happen. Medical Journal of Australia 174(10), 516–519.
VGDHS (1999) Victoria Burden of Disease Study: Morbidity. Victorian Government Department of Human Services Melbourne, Victoria, Australia.
Waldenstrom, J., Broman, T., Carlsson, I., Hasselquist, D., Acherberg, R.P., Wagenaar, J.A. and Olsen, B. (2002) Prevalence of Campylobacterjejuni, Campylobacter lari, and Campylobacter coli in different ecological guilds and taxa of migrating birds. Applied and Environmental Microbiology 68(12), 5911–5917.
WHO (2002) Guidelines for Drinking-water Quality. Second Edition. Addendum: Microbiological Agents in Drinking Water. World Health Organization, Geneva, Switzerland.
WHO (2003) International Statistical Classification of Diseases and Related Health Problems, 10th Revision. Version for 2003. World Health Organization, Geneva. (http://www.who.int/classifications/icd/en/ Accessed November 2006)
WHO (2005) Disability weights used in the Global Burden of Disease 1990 study. (http:// www3.who.int/whosis/menu.cfm?path=evidence,bod,burden,burden_manual,burden_ manual_other&language=english). Accessed November 2006

APPENDIX 3.1 SUMMARY OF INFECTION PARAMETERS
Table A3.1 shows the severity weights, durations and incidence for various forms of infection for both Campylobacter spp. and Cryptosporidium spp. taken from Havelaar et al. (2000a,b) and Mead et al. (1999). The remaining Tables outline the @Risk input values and sensitivity analysis data.
Table A3.1. Severity weights, duration and incidence

Infection Severity Duration
(days) Incidence* Age at
death
Uncomplicated campylobacteriosis 0.086 6 30% –
Complicated forms of campylobacteriosis 0.28 365 0.5% –
Fatal cases of campylobacteriosis 1 0.005% 78
Cryptosporidiosis (normal population) 0.054 6 71% –
Cryptosporidiosis (immunocompromised) 0.13 47 100% –
Fatal cases of cryptosporidiosis 1 0.022% 78

* Incidence for uncomplicated campylobacteriosis and cryptosporidiosis in the normal and immunocompromised populations relates to the percentage of people in whom infection goes to clinical illness. The other incidence figures are a proportion of those showing clinical illness.
Campylobacter spp. through toilet flushing
Table A3.2. @Risk input values and sensitivity analysis

Input Distribution Mean Range Regression
value
Volume ingestion (ml) Normal 0.1 0–0.25 0.59
Campylobacter concentration (/ml) Log Normal 0.00 1 0–0.00056 0.46
Frequency of contamination of harvested supplies Normal 3 0–10 0.42
Number of flushes Discrete 3–6 0.31

Campylobacter spp. through direct ingestion (external tap use)
Table A3.3. @Risk input values and sensitivity analysis

Input Distribution Mean Range Regression
value
Percentage of children exposed Normal 2.5 0–5 0.52
Campylobacter concentration (/ml) Log Normal 0.0025 0–0.0056 0.52
Frequency of contamination of harvested supplies Normal 3 0–10 0.49
Frequency of drinking
from external tap Normal 7.5 3–12 0.29
Volume ingested (ml) Normal 125 50–250 0.17

Campylobacter spp. through cross connections (contaminated potable supplies)
Table A3.4. @Risk input values and sensitivity analysis

Input Distribution Mean Range Regression
value
Households affected by
cross connections Discrete 0–2 0.78
Campylobacter concentration (/ml) Log Normal 0.00125 0–0.0028 0.35
Frequency of contamination of harvested supplies Normal 3 0–10 0.31
Length of cross connections (days) Normal 33 10–60 0.03

Cryptosporidium spp. through direct ingestion (external tap use)
Table A3.5. @Risk input values and sensitivity analysis

Input Distribution Mean Range Regression
value
Cryptosporidium concentration (/l) Log Normal 3 0–50 0.63
Percentage of children exposed Normal 2.5 0–5 0.45
Frequency of contamination
of harvested supplies Normal 3 0–10 0.42
Frequency of drinking from external tap Normal 7.5 3–12 0.24
Volume ingested Normal 125 50–250 0.15

Cryptosporidium spp. through cross connections (contaminated potable supplies)
Table A3.6. @Risk input values and sensitivity analysis

Input Distribution Mean Range Regression
value
Number of households affected by cross connections Discrete 0–2 0.70
Cryptosporidium concentration (/l) Log Normal 1.5 0–25 0.43
Frequency of contamination
of harvested supplies Normal 3 0–10 0.29
Length of cross connections (days) Normal 33 10–60 0.02

Cryptosporidium spp. through contaminated garden produce
Table A3.7. @Risk input values and sensitivity analysis

Input Distribution Mean Range Regression value
Cryptosporidium concentration (/l) Log Normal 3 0–50 0.80
Frequency of contamination
of harvested supplies Normal 3 0–10 0.52
Residual water (ml) Normal 3.75 3–4.5 0.11
Volume of lettuce ingested (g/week) Normal 51.9 30–90 0.04

REFERENCES
Havelaar, A.H., de Wit, M.A.S., van Koningsveld, R. and van Kempen, E. (2000a) Health burden in the Netherlands due to infection with thermophilic Campylobacter spp. Epidemiology and Infection 125, 505–522.
Havelaar, A.H., de Hollander, A.E.M., Teunis, P.F.M., Evers, E.G., van Kranen, H.J., Versteegh, F.M., van Koten, J.E.M. and Slob, W. (2000b) Balancing the risks and benefits of drinking-water disinfection: disability-adjusted life years on the scale. Environmental Health Perspectives 108, 3 15–321.
Mead, P.S., Slutsker, L., Dietz, V., McCaig, L.F., Bresee, J.S., Shapiro, C., Griffen, P.M. and Tauxe, R.V. (1999) Food-related illness and death in the United States. Emerging Infectious Disease 5(5), 607–625.

 

Save your money…save your water…save your environment!

http://www.combinedharvesters.com

The rapid expansion in companies who supply rainwater harvesting of varying quality has resulted in the publication by British standards BSI-code of practice BS8515:2009. This guide has been produced to assist architects, construction companies and contractors to comply with the new standard in the same way that all systems from combined harvesters do.

Welcome from the combined Harvesters team

Formed early in 2006, Combined Harvesters have grown to become one of the foremost suppliers and fitters of all types of rainwater harvesting systems from simple water butts to full underground storage systems and all associated integral parts.
We, unlike a great many companies, are not affiliated with one supplier but source our products based on market trends and the specific needs of our clients.
With such a comprehensive range of products on offer, we believe our service to be second to none in the industry and one which we continually strive to improve.
Our business history is not quite so young as Combined Harvesters however, we have been in landscape construction and design for 30 years in both the domestic and commercial sectors which has given the team great knowledge and experience to bring to this blossoming sector.
When you deal with us, you are not only getting fast, friendly advice from a family owned and run company but you will get the benefit of our integrity and business skills to give you the most comprehensive system, specifically tailored to your needs within your budget.

Below are a few frequently asked questions to assist with the guide BS8515

What is Rainwater Harvesting?

Rainwater harvesting is a way of saving the rainwater which would normally flow off a roof and down the drain, and using it as piped water to flush toilets and for the garden watering, yard washdown, vehicle and car washing, and even for your washing machine, instead of using expensive treated drinking (potable) water.

Are there planning regulations associated with rainwater Harvesting?

They are not required directly by Building Regulations, although they may be linked with the Planning Permission for the storm-water management of the site. Building Regulations do cover the installation itself, tank siting & pipe runs etc.

Will a system affect my homes eco rating?

Yes, rainwater harvesting is an important ER criterion. The EcoHomes rating system addresses all aspects of reducing potable water demand in a dwelling. Installing a rainwater harvesting system adds to the credit rating for water use.

What types of rainwater harvesting systems are there?

Un pressurised: rainwater is gravity fed from a header tank, usually in the loft to the point of use.
Pressurised: The rainwater is pumped directly from the above or under-ground tank to the required point of supply. i.e. toilet, outside tap etc.

Is there a danger of legionella?

No, the system does not provide the conditions necessary for the cultivation of Legionella. With the water stored underground it is dark cool and is kept well oxygenated. Legionella cannot cultivate in these conditions.

How is the system maintained?

Filters should be thoroughly cleaned once a year and we recommend a full ‘flushing’ of the system every three years. A treatment with an anti-algicide such as sprayguard is also recommended. A correctly designed harvesting system overflows on a regular basis to remove floating matter and the pumps are very reliable. Maintenance should only be carried out by qualified or experiences personnel. Combined harvesters have their own teams available year round to keep systems working efficiently.

What kind of pumps are used in the systems?

Pumps can be housed either internally in the tank or mounted within a control unit fitted in a garage, plant room etc. Pumps should have run dry protection and should have a pressure switch fitted to stop hunting. Internal tank pumps need to be constantly submersed in water to prevent damage from the air, from debris or sediment that may be sucked in. An external pump or control unit should have an audible alarm to identify faults in the system, when fresh water is being used etc.

How much does it cost to run a rainwater harvesting pump?

It typically takes 1.5- 2.0 kWh to pump 1 cubic meter of water (1000 litres). For a typical house using rainwater for WCs, washing machine and the garden, pumping costs are between 5-10p per week

Do I need to have a water meter?

This is not generally necessary; however the absence of one will reduce you seeing the benefits of harvesting rainwater immediately.

What does the British Standard BS8515:2009 cover?

BS8515 covers the design, installation, water quality, risk management and maintenance of rainwater harvesting systems. This applies to both new and retrofit properties.

What is the payback period?

This figure will depend upon the rainwater that you collect and the use. A typical domestic client will see a payback between 5-10 years. Commercial clients can reduce this figure to 2-5 years.

Is it only for new builds?

No systems can easily be retro-fitted

What design aspects are to be considered to comply with BS8515?

Designs should be provided by an industry expert, amount and intensity of rainfall, type of intended applications both now and in the future will be considered. Tank size will depend upon ground conditions and surface water. All these as well as filtration requirements, end use by clients, site restrictions and other factors not necessarily covered by BS8515 will be considered when designing a system.

What happens when there is no rain?

In the absence of no rain, correctly designed systems will have a ‘mains top up’ facility. This will fill the tank with the minimum required amount of water to keep it functioning until the rain returns..

Is rainwater harvesting suitable for work as well as at home?

Yes, in schools, hospitals, offices, commercial premises, rainwater can typically be used for toilets, vehicle washing, yard wash down and watering plant pots/gardens.

Can it be used when there is a hosepipe ban?
It is possible to use a hosepipe connected to a rainwater tank, provided that the tank is not connected to a mains water supply. Many people are doing this already by using a water butt.

Is it only for houses?

No, bungalows and commercial premises are also very suitable, the only limitation is the area of the roof to capture rain, in fact commercial and industrial buildings can make the largest savings.

Where is it installed?
The tank should be buried under a car or vehicle park, landscaped area, garden, patio or drive, with space left for the round access cover. Most systems are designed so that they can accept cars driving over them if suitably installed. Or an above ground system can be installed next to the house or property.

Are there any grants available?

Not for domestic installations yet, although several organisations are petitioning the government for assistance. For commercial installations, there is a tax relief scheme (ECA) for suitable approved equipment on the Water Technology List.

How clean is the water?

The rainwater is filtered as it enters the storage tank, to remove particles and other matter. It is kept in the dark and kept oxygenated to discourage algal growth, and properly designed systems are designed with calming inlets, which ensure that any sediment at the bottom of the tank does not get stirred up. The water is not drinking water fit for humans.

How do you stop debris from entering the system?

A filter is fitted along with a ‘calming inlet’. The filter has to meet strict criteria covering its weather resistancy, accessibility and efficiency.

How much rainwater does a system collect?

This depends on the area and angle of your roof, and your rainfall. Averages of 100,000 litres per household are commonly quoted, much more for large roofed commercial buildings. An average system for a family is 3800litres.

Is the tank covered by BS8515:2009?

Yes, all tanks are covered. They need to be water tight, discourage microbial growth, avoid stagnation and thereby legionella .Tanks need to be suitably load bearing and need to resist floatation.
Pipes to and from the tank need to be clearly marked, rainwater pipes can be green or black (not blue) .Special marker tape can be purchased to show piping on a scan.

Does the tank need an overflow?

Yes, the overflow needs to be the same diameter or even larger than the inlet, it must also be fitted with back flow prevention. Overflows are important as a tank should be the correct size so as to overflow at least twice a year to ‘flush the system’.

How much would this save on water bills?

Depending on your normal usage, it can save 30 to 50% for the domestic user and 80% for the commercial user of the treated drinking water from the mains. Having metered water is the best way of appreciating the difference.

So, why should people buy Rainwater Harvesting systems?

To save on water bills and show they use water, an increasingly precious resource, responsibly to make a difference to our environment.

How does rainwater harvesting work?

A storage tank is fitted to your storm water drain from your roof, and falling rain enters the tank through a filter which removes leaves and other matter. The storage tank is usually buried under car or vehicle parks, a garden or under the entrance access or drive, and contains a pump which pumps the rainwater to the building where it is piped to the toilets, and to the outside taps. Above ground tanks are also available.

How much water can a system save?
Depending on your normal usage, it can save 30 to 50% of the treated drinking water from the mains in houses and up to and up to 80% of the treated drinking water in a business or commercial building.

What can you use the water for?

Filtered, untreated rainwater should only be used for non- drinking or bathing purposes: toilet flushing, gardens and vehicle or yard wash downs.

How much does it cost?

Domestic systems can cost from about £2500 up to £4000 plus including installation costs, depending on size of tank. Commercial systems can cost a lot more depending on size and requirement, but usually have a much quicker ‘pay back’ period due to the size of roof and high usage.

Could rainwater get into my drinking supply?

Not in a properly designed system, the pipe work is entirely separate and should be identified as non-potable. BS8515:2009 stipulates that backflow prevention should be fitted upstream of or at a point where any two systems meet. This form of back flow prevention must be of type AA or AB Air gap conforming to BS13076 and BS EN13077.

Do I need a big roof area to make it worthwhile?

No, most domestic roofs are more than adequate, but the bigger and flatter the roof area, the more rain will be captured, and the more the rainwater will substitute for treated mains water.

Is Rainwater Harvesting a new idea?

No, collection re-use of rainwater from roofs can be traced back thousands of years in hot, dry countries around the Mediterranean. In continental Europe, some 100,000 are installed annually; Germany has been using and refining the technology since the early 80s.

Can a roof affect the efficiency of a system?

Yes, all these need to be free-draining and suitable to stop debris from entering the system. Other roofs such as green roofs etc absorb water and results in less run off and more colouration.

This guide has been produced to assist professionals who are interested in the specifications of rainwater harvesting systems. Enabling them to make an informed choice of supplier based on the criteria set down in BS8515:2009. At Combined Harvesters Ltd we are committed to a long term approach to the supply of all rainwater harvesting and stormwater management products, ensuring quality throughout the chain.

Save your water…save your money…save your environment.

Parts of south-west England saw 45 days without any rain in the summer of 1976

Is Britain prepared for drought?

Can you advertise British weather to tourists?

‘We’re planning for the worst’

The environment secretary is to meet water companies, farmers and wildlife groups amid fears that parts of Britain may face the worst drought since 1976.

 

Parts of south-east England, East Anglia and the east Midlands are among the worst affected areas.

 

Trevor Bishop, head of water resources at the Environment Agency (EA), says it is “planning for the worst”.

 

Water restrictions could be introduced unless heavy and prolonged rainfall takes place before April, the EA warns.

 

The Department for Environment, Food and Rural Affairs (Defra) called Monday’s summit to look at how to deal with the drought.

 

Environment Secretary Caroline Spelman will meet water companies – who are encouraging customers to cut down on consumption – along with other concerned groups.

 

A lack of rainfall over the past few months means groundwater levels are still falling in many areas.

 

Last month EA experts said water levels were so worryingly low that twice the average rainfall was needed if rivers are to recover and a hosepipe ban is to be avoided.

 

Stranded fish

Continue reading the main story

“(We want to) support people in doing the right thing in taking sensible measures to save water”

Caroline Spelman

Environment Secretary

“We’re reaching the end of the second consecutive dry winter and that’s very unusual so the situation is getting quite serious across the east of England, the Midlands and the south-east,” Mr Bishop told BBC Radio 4’s Today Programme.

 

“It’s not quite as bad as the situation we saw in 1976, but it’s unusually close so we’re planning for the worst.”

 

The EA, which covers England and Wales, has had to oxygenate rivers and move fish that have become stranded in isolated pools and farmers have been prevented from drawing water from rivers in some cases.

 

It is very unusual to be carrying out this kind of activity at this time of year, Mr Bishop said.

 

This week the Centre for Hydrology and Ecology reported that average rainfall so far this winter was the lowest since 1972.

 

Northamptonshire has had the driest 16 months since records began and the eastern region of England has had its driest spell in 90 years, the EA said.

 

Paul Valleley, director of water services at Anglian Water, said it was monitoring the situation very closely but the likelihood of a hosepipe ban was increasing if it remains dry.

 

 

“We do have some reservoirs that are 20% below where we would ideally like them at this time of year,” he said.

 

“It really does now depend on how the weather goes in the coming weeks and months as to how much of that water we do recover.

 

“If it remains dry then we will have a problem coming into the summer.”

 

Water companies, the EA, Natural England, British Waterways, the Met Office, representatives from the agricultural sector and environmental non-governmental organisations will be at the summit, Defra said.

 

Ms Spelman said: “All of our activity is going to be carefully co-ordinated so that we are able to minimise the effects of unpredictable water availability and support people in doing the right thing in taking sensible measures to save water.”

The teacher and the taught

A young teacher from an industrial city in the north of England had accepted a temporary job teaching a class of four-year-olds out in one of the most isolated, rural parts of north Wales. One of her first lessons involved teaching the letter S so she held up a big colour photograph of a sheep and said: “Now, who can tell me what this is?”

No answer. Twenty blank and wordless faces looked back at her. “Come on, who can tell me what this is?” she exclaimed, tapping the photograph determinedly, unable to believe that the children were quite so ignorant. The 20 faces became apprehensive and even fearful as she continued to question them with mounting frustration.

Eventually, one brave soul put up a tiny, reluctant hand. “Yes!” she cried, waving the snap aloft. “Tell me what you think this is!” “Please, Miss,” said the boy warily. “Is it a three-year-old Border Leicester?”