Private Water Supplies

In general terms, a private water supply is any water supply not provided by a water company. It is not a "mains" supply. Most private supplies are situated in the more remote, rural parts of the country. The source of the supply may be a well, borehole or spring. The supply may serve just one property or several properties through a network of pipes.

There are 223 private supplies serving over 400 properties within Stratford-on-Avon district. There are a certain number of domestic and commercial private water supplies where we routinely monitor quality both microbiologically (bacteria) and chemically (e.g. nitrates). We decide which category the supply falls into and the risk; this tells us how often we have to test the water. Testing of supplies to a single domestic dwelling is only carried out if the homeowner requests it.

Safe drinking water is essential to good health. All private water supplies can pose a threat to health unless they are properly protected and water treated. They may become contaminated with bacteria, protozoa, parasites and viruses (micro-organisms) or other substances. Many of these are harmless, but some may cause serious illness or even death in vulnerable people. We risk assess commercial and larger domestic water supplies at least every five years. This involves looking at the whole supply from source to point of use and identifying any problems that may cause the supply to become contaminated.

Many private supplies need treatment to remove contamination. This is especially true for a supply of water from a spring source, which is prone to contamination from bacteria in the environment.

Treatment Methods

Some treatment methods include:

  • sediment filters
  • ultraviolet (UV) disinfection units
  • reverse osmosis systems
  • ceramic filters
  • nitrate filters

Ultraviolet Treatment

UV treatment is by far the most common form of treatment system and, if correctly maintained, can be highly effective. Here are some tips on what to look for:

  1. If you have a UV system installed you should make sure that it is the correct size for the consumption (by asking a specialist).
  2. You should ensure that the system is serviced at least annually (UV bulbs lose their effectiveness overtime, although the bulb may still appear to be working).
  3. When bulbs are replaced, the crystal sheath inside the unit must also be cleaned. The light can be prevented from working if dirty.
  4. You should have a pre-filter (of maximum 5 micron pore size) before the filter to prevent particles from stopping effective treatment.

Notification Requirements

Property Owners

If you own a property on a private supply you should contact us to ensure that we are aware of your supply. If your property serves a single property and is not let out or used for a commercial purpose, there is no requirement for us to inspect or monitor the supply, but this can be undertaken on request (fee payable).


If you are a landlord of a property on a private supply you must notify us that the property is tenanted, as we will require the supply to be risk assessed and regularly sampled (even if you are not owner of the source supply).

Commercial Premises

If you run any kind of commercial premises you should contact the local authority; some commercial activities require more frequent sampling.

Holiday Lets

If you run a holiday let and you are on a private supply, it is still classed as a commercial activity and you should notify us as we will need to risk assess and sample the supply.


If you rent your property and it is on a private supply, it is classified as a commercial supply and should be sampled annually. You should ask your landlord if you suspect the supply is private. You can contact us on the details below if you are concerned that you are in a tenanted property with a private supply that has not been checked.

Further Information

The Environmental Protection team liaises with water companies in our district in relation to health aspects of public water supplies. If you have problems with your mains supply or have concerns over its quality, you should contact your water company.

Further information on private water supplies can be found on the DWI website.

You can also contact the Environmental Protection team:

Contact: The Environmental Health team

Last updated on 22/11/2021