Private water supplies

The Water Industry Act 1991 requires local authorities like us, to check the wholesomeness and sufficiency of private water supplies provided to premises in their area.

The regulations under which Private Water Supplies (PWS), are inspected are The Private Water Supplies Regulations 2009. These came into force on 1 January 2010 and introduced several differences from the previous regulations.

The regulations require the Local Authority to complete a risk assessment of all private water supplies, except for supplies to single non-commercial domestic dwellings. This has to be done within five years of the regulations coming into force and subsequently every five years thereafter. Risk assessments involve looking at the whole private water supply including the source, any storage tanks, any treatment systems and the premises using the supply.

There are also changes to the sampling that we must carry out. Large supplies (greater than 10m3/day) and supplies that provide water for commercial activities require check and audit sampling to be carried out. Check sampling involves looking at a suite of basic parameters, audit sampling covers a much larger suite of parameters. The frequency of these sampling suites depends upon the volume of water used from the supply. For example:

  • ≤ 10m3/day - sampling frequency 1 sample per year
  • >10 ≤ 100m3/day - sampling frequency 2 samples per year
  • > 100 ≤ 1,000 - sampling frequency 4 samples per year
  • > 1,000 ≤ 2,000 - sampling frequency 10 samples per year...

There are also new procedures that local authorities must follow if a private water supply is determined as being unwholesome under the regulations. This includes a requirement to investigate the cause of any failures, inform users of the supply if it poses a potential danger to human health and giving advice to users to minimise any such potential dangers. Enforcement powers are available if needed.

Changes have been made to the charges that can be made, including the introduction of new charges for carrying out risk assessments and enforcement work. For these charges see  Private Water Supplies Fees [13kb].


Private water supply

In general terms a 'private water supply' is any water supply which is not provided by a Water Company. It is not a mains supply and no water rates are paid, although the person who owns the supply may make a charge. There are no laws controlling the charges or other conditions connected with private supplies. The owner or person who uses the supply is responsible for repairing and maintaining it. Private supplies are commonly used in the rural parts of Mid Devon.

A private water supply could serve just one property or it could be a large supply with a network of pipes supplying water to many properties. The water may come from a spring, well, borehole, pond, river or stream.

Quality standards for water

Good quality water is very important to everyday life. Every house must have a good supply of clean, fresh water for it to be fit for occupation.

To make sure that water used in the home and for producing food is of the high quality required to protect public health, the government has set legal quality standards which all water used for drinking, washing and cooking or used in businesses which produce food or drink must meet. Private supplies are more likely to be contaminated because the sources are more likely to be unprotected from contamination and they are generally not treated to the same standard as public supplies.

Water supply categorisation

There are five categories of supply:

  1. Commercial - supplies water to a premises where the water is used for a commercial activity
  2. Large supplies - an average daily volume of water of 10 cubic meters or more
  3. Private Distribution System - the water is supplied by a water undertaker or licensed water supplier and then further distributed by a person other than the water undertaker or licensed water supplier
  4. Small Private - the water is supplied to more than one domestic dwelling
  5. Single Private Dwelling - a domestic dwelling

Water sampling frequency

Large or commercial supplies will depend on volume as outlined above. Small Private supplies must be monitored at least every 5 years.

Further information

For further information see the following links:


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