Questions to ask before buying a house with its own private water supply

Buying a house with a Private Water Supply

We strongly recommend that prospective buyers of properties/homes with there own private water supplies read this document. The primary source of this advice is the drinking water inspectorate website.

Key questions

The questions listed at the end of this document are designed to be asked of the owner of the property (through a solicitor or estate agent), or the local authority who regulate private water supplies. Environmental Health Officers are required to establish water quality, the health risks and the future cost liability.

What is a PWS A private water supply?

A PWS is one which is not provided by a water company. About 1% of the population in England and Wales do not have a public supply of mains water to their home and instead rely on a private water supply. Mostly, but not exclusively, these occur in the more remote, rural parts of the country. A  private supply source can be a well, borehole, spring, stream, river or lake and it can also involve storage structures or tanks. Some supplies may serve just a single property or they can be much larger serving many properties and businesses through a network of pipes. Under rare circumstances you may be supplied with mains water by your water company but not receive a bill. In these circumstances you may be receiving a supply through a Private Distribution System.

Single dwelling with its own supply

The regulations do not require a risk assessment If the supply is to a single dwelling and is used only for domestic purposes? The owner can request a risk assessment. In an ideal situation the owner of the supply would have had a risk assessment and monitoring carried out prior to purchasing a property. The risk assessment helps determine the wholesomeness and sufficiency of a supply.

Shared supply

If the supply is shared by two or more properties, then the local authority are required to risk assess the supply and monitor it by sampling at an appropriate frequency.

Risk Assessments

Risk assessments investigate and report on the source of the supply, the surrounding area, water storage tank and treatment, right through to the taps. The aim is to identify any actual or potential contamination. Prospective buyers may also wish to check whether there is any agreement among other property owners as to how these costs are shared or covered. Is remedial action required and how are the costs shared and who is responsible for managing the costs?

Key questions to ask before buying a house with its own private water supply

    • Has a risk assessment already been carried out by the Local Authority, and if so when?
    • Did the local authority advise that improvement works were required?
    • What were the results of any previous sampling by the Local Authority?
    • Did any results indicate a water quality problem? c) Individual premises
    • Are there filters or UV disinfection units installed in the property?
    • Was the equipment installed by a competent installation and Is the treatment appropriate?
    • Is the system compliant with Regulation 5 of the PWS regulations?
    • Is the UV system WRAS approved for use on a drinking water supplies?
    • Has the current owner got any maintenance logs or records for the supply?
    • Are there any compliant spare parts for the supply, including any treatment system?
    • Have there been any problems with the supply such as taste and odour, discolouration or insufficiency.
    • Are there any documented instructions detailing the procedures should any problems with the supply arise, e.g. sufficiency or water quality such as taste or odour issues. These should contain telephone numbers or other contact details to arrange for alternative supplies, pipe repairs, treatment system maintenance etc.
    • Is there a schematic of the supply showing the layout of pipes, tanks, inspection chambers etc. available?
    • Are there schematics or plans for  various parts of the treatment system, stating what each part is, for example any filters, iron or manganese removal systems, and disinfection?

Water testing and report

Springhill Water have been treating private water supplies for nearly 20 years. Contact us on 01422 833121 to arrange a site visit or if you have any questions or would like advice.

Our standard price for testing and a report is £180 plus VAT.

How can a private water supply affect health? Literature review 2008

How can a private water supply affect health? Literature review 2008

Mains water vs Private Water Supply

The quality of drinking water supplied to those people on the mains in the United Kingdom is regularly analysed to make sure that it meets the standards set by the European Commission. The responsibility for independently monitoring the water companies rests with the Drinking Water Inspectorate (DWI) and they advise the government of their performance. According to the report submitted by the Chief Inspector of the Drinking Water Inspectorate (DWI, 2005), English water companies carried out just over 1.8 million tests and the mean compliance rate was 99.94%. On a local level, Yorkshire Water carried out 447,822 tests with a compliance rate of 99.97%. The DWI (2005) report these statistics as showing that the water provided by this company is generally of a very high quality and the health risks relating to drinking mains water remains low. However,  Medema et al. (2003) believes the microbiological quality of water should remain a cause of concern for all water suppliers, regulators and public health authorities as the potential for drinking water to transport microbial pathogens to great numbers of people causing subsequent illness, is well documented in all countries at all levels of economic development.

Untreated water from a private water supply can be harmful to health

Private water supplies are not regulated by the Drinking Water Inspectorate, but are the responsibility of local authority environmental health departments who must register the supplies and approve them based on a regime of chemical and microbiological analysis of water samples (Smith et al., 2006).

The report on the outbreaks of waterborne infectious intestinal disease in England and Wales (Smith et al., 2006) reports 89 outbreaks of waterborne diseases affecting 4321 people in England and Wales for the period 1992 to 2003. Public water supplies were implicated in 24 outbreaks (27%); private water supplies in 25 (28%); swimming pools in 35 (39%) and other sources in five outbreaks (6%). There are 56 potentially pathogenic organisms that can be found in drinking-water (Clapham, 2004) with the majority of waterborne outbreaks in private water supplies caused by Campylobacter, E.coli 0157, Cryptosporidium and Giardia (PWS Technical Manual, 2007). Supporting this view, Said et al. (2003) identified the pathogens infecting private water supplies in the period 1970 to 2000, based on 25 reported outbreaks, as being Campylobacter 13 (52%), Cryptosporidium and Giardia 4 (16%), Cryptosporidium and Campylobacter 2 (8%), E.coli 0157 1 (4%). No pathogens were identified in 4 (16%) despite microbiological investigation. One of the outbreaks (4%) implicated Giardia and/or Campylobacter, but no actual causation agent was identified. Other pathogens of potential concern are Streptobacillus, Enteric viruses and Paratyphoid, however, these pathogens are rarely found in United Kingdom private water supplies (DWI, 2001).

Illness from a private water supply is 35% higher than from mains

The report on outbreaks of infectious disease associated with private drinking water supplies in England and Wales for the period 1970 to 2000 (Said et al., 2003) reports the incidence rate of outbreaks for recipients of private water supplies may be as high as 35 times the rate of those receiving public water supplies. The figure of 35 was based on 53 outbreaks per million population on mains supplies compared to 1830 outbreaks per million population for private water supplies. Clapham (2008) believes the figure for outbreaks for private water supplies is closer to 50 times higher than that of a mains supply if only the figures for the last 10 years are considered.

The most common symptoms

The Said et al. (2003) report highlights 25 outbreaks with private water supplies and subsequent investigations identified 1584 cases and at least 5190 people at risk. The most common symptoms were gastrointestinal and there were no recorded secondary cases of death, although there were several hospital admissions. Clapham (2004) believes these figures underestimate the true number of outbreaks for private water supplies because of general under-reporting of gastrointestinal illness. Supporting evidence for this view is contained in a paper by Wheeler et al. (1999) which concluded that for every case of infectious intestinal disease identified by the national surveillance system, another 1.4 were identified by laboratories. This study concluded that infectious intestinal disease is common, with 9.4 million estimated cases each year in England. However, only 1.5 million were presented to a general practitioner and only a fraction of cases involving Campylobacter being reported to national surveillance.

Drinking water from a private water supply can cause diarrhoea and vomiting

Drinking water from a private water supply can cause diarrhoea and vomiting

What is a private water supply? Literature review 2008

What is a private water supply? Literature review 2008

Academic literature review on UK Private Water Supply: Author Geoff Nemec

Although most people living in the United Kingdom have access to water supplied by a public water company many rural communities rely solely upon untreated private supplies for their drinking water. A private water supply can be defined as a supply of water not provided by a statutory water company, large authority or corporation.

Other Definitions

Other definitions include; small water supply; rural water supply; community supply or even non-community supply (Clapham, 2004).  Owners of these supplies often refer to them as springs, wells, boreholes, or watercourses and the premises served can be individual houses, farms or businesses, small settlements or villages. The Manual for Private Water Supplies (PWS Technical Manual, 2006) defines a private water supply as a supply not provided by a statutory water undertaker and where the responsibility for its maintenance and repair lies with the owner or the person using it. In some cases a private water supply may only serve a single household and provide less than one cubic metre of water per day or they may serve several properties or commercial / industrial premises and provide 1,000 cubic metres of water, or more each day (Jackson et al., 2001).

1% of UK on a Private Water Supply

Approximately 1% of the United Kingdom population (600,000) derive their potable water from 140,000 private water supplies (Kay et al., 2007). A breakdown of current estimates broadly suggests there are; 50,000 supplies (Jiggins, 2007) in England and Wales serving 330,000 (approximately 0.6%) people with 30,000 of the supplies serving a single dwelling (Jiggins, 2007); 38,000 private water supplies in Scotland (DWI, 1993 cited Reid et al., 2001) serving an estimated population of 60,171 (approximately 1.18%) of the Scottish population (Reid et al., 1999, cited Reid et al., 2001); 1,269 private water supplies in Northern Ireland, 1,152 of which are used by dairy farms (Department of Agriculture and Rural Development, 2008).

Calderdale higher than average number of Private Water Supplies

Barraclough et al. (1988) estimated that the number and nature of private water supplies in Calderdale and from these findings Collinge (1989) determined that over 5,000 people, equating to approximately 2.7% of the population in Calderdale were being served by private water supplies. That means Calderdale has more than the average number of Private Water Supplies.

Many rural areas have boreholes and spring water supplies

Many rural areas have boreholes and spring water supplies



When the rain comes?

clean and dirty filters

Research shows that Spring supplies are most likely to contain Faecal Coliforms (E.coli) within 3 days of heavy rainfall. The level of contamination is much higher after a long dry spell as the rainfall collects layers of detritus matter that has built up over the summer months. This means that clean filters can become blocked very quickly. The guiding principle is, if the inside of your filter is discoloured, then it is time to change the filter. This will avoid ‘breakthrough’ whereby contaminants overwhelm the filter leading to discolouration of water and the blinding of quartz sleeves.