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.
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.
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 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.
True spring supplies are rare in the UK. Even if shown on a map as a spring, the chances are that the water is not coming from deep underground.
Surface derived source
Most ‘springs’ in the UK can best be described as surfaced derived sources. This is because the water probably never passes more than a meter below the surface. The top layers of soil acting a sponge that slowly releases water throughout the year. The water having passed through the top layers of soil, hit shale or rock and then run horizontally. Culverts, land drains, ditches and a under ground pipe channel the water to a collection chamber. Water from the chamber is then piped down to a property, or several properties.
A boggy bit o land
Listen to this short humorous account of what most springs actually are – A bogyy bit o land.
Even when a spring is shown on a map as a spring, the chances are that it is in fact a surfaced derived sources. Springs are rare in the UK as they require a rare type of geology. In the vast majority of cases the water from these ‘springs’ rarely passes more than a meter below the surface. Even in those rare cases where the water rises from deep below ground, the most vulnerable point of contamination is where the water ‘springs’ from the ground and mixes with surface run off, especially after heavy rainfall or a snow melt.
True ‘spring water’ can be of good quality but it must be protected from possible contamination once it has reached ground level. In particular, it is necessary to consider the possibility of pollution from septic tanks or from agricultural activities.
A small collection chamber built over the ‘spring’, see Schematic One below, will offer some protection from surface water run-off, but the risk of the water containing pathogens will remain high. This is because water entering the collection chamber is likely to have already been contaminated.
However, building a collection chamber will offer some protection against surface pollution and will provide a small amount storage in periods of high demand and serve as a header tank. The collection chamber should be built so that the water enters through the base or the side. The top of the chamber must be above ground level and it should be fitted with a lockable watertight access cover.
Private water supply spring collection chamber
Fenced off area around the Collection Chamber
An overflow must be provided appropriately sized to take the maximum flow of water from the spring. (See schematic Two below). The outlet pipe should be fitted with a strainer and be situated above the floor of the chamber. The chamber should be built of a material that will not impair water quality and be designed to prevent the entry of vermin and debris.
The area of land in the immediate vicinity of the chamber should be fenced off and a small ditch dug up-slope of the chamber to intercept surface run-off.
Take great care when digging around a spring source
We strongly advice that great caution is exercised when digging around a source. Disturbing the top layers of soul, a ditch, or a boulder above or below the point where the water springs to the surface could result in the water taking a new route. In some cases, this can result in the water course being changed permanently.
Fenced off area around a private water supply spring collection chamber
Acknowledgement: The primary source of information whilst preparing this document is Drinking Water Regulator in Scotland (DWRS).