A private water supply is any water supply which is not provided by a water company (mains drinking water). They are mainly located in the more rural parts of the county borough. 

A single supply point may serve just one or several properties.

Types of private water supplies

Underground sources (including boreholes, springs and wells)

These types of private water supplies draw their water from deep underground and are less likely to be contaminated with micro-organisms, though they may contain minerals and other chemicals.

However underground sources are at risk of contamination at the surface extraction point where surface water may gather or flow into the supply. Shallow wells may also be susceptible to contamination carried by surface water or activities on the land such as fertiliser spreading.

Surface sources (including rivers, streams, lakes and ponds)

These types of private water supply can be contaminated by micro-organisms especially during periods of rainfall. Rainwater can run across the ground collecting contamination from various sources (for example from the soil or animal droppings) which is then deposited into the water source. 

Surface sources may also dry up during prolonged periods without rain.

Our advice on loss of water from private water supplies also describes ‘onward distribution’ or ‘private distribution’ networks. These networks are also classed as private water supplies under The Private Water Supplies (Wales) Regulations 2017.

Contamination and treatment

Private water supplies can become contaminated with a range of micro-organisms and chemicals.  It may not be possible to tell if your water is contaminated by taste, sight or smell.

While most are harmless, some types of contamination can cause serious illness or reduce the effectiveness of treatment processes. 

Types of contamination

Micro-organisms (also known as bacteriological)

Anyone who consumes water contaminated with micro-organisms is at risk of infection which can result in a number of serious illnesses. The risk is especially high for people who are not used to your water. If your pets drink the water they may become infected and this infection could be transmitted to humans.

For example, Escherichia coli (E.coli) and Enterococci are bacteria found in the gut of warm-blooded animals. They should not be present in drinking water and, if found, immediate action is required to identify and remove any source of faecal contamination. The standard is 0 per 100ml.


Private water supplies can become contaminated as a result of chemicals:

  • being used in farming or other land management areas (for example pesticides)
  • occurring naturally in the ground (mainly minerals, such as iron) which may affect the appearance/taste of the water and can reduce the effectiveness of treatment equipment
  • being used in industrial or commercial processes (for example solvents)
Lead contamination

Lead may be present in your water as a result of the plumbing at the property (where there are older lead pipes or holding tanks, or lead solder has been used on copper pipes). While there are treatment methods available to deal with lead it is best to replace any lead plumbing. Water that has been left to stand in lead pipes for long periods (for example overnight) should be left to run out of taps for approximately one minute before using. 

If you need further advice or would like your water testing for lead, contact our Environmental Protection team.


Good water quality is essential to good health. The drinking water from a mains supply goes through several intensive purifying processes at the treatment plant before reaching consumers. This is often not possible with private water supplies, but there are techniques that can be used to make sure the supply is safe to drink.  

Micro-organism contamination can usually be treated by filtering the larger impurities; followed by ultraviolet (UV) sterilisation. Both filtration and UV sterilisation systems require regular maintenance to be effective.

Be aware of what can influence your water supply

The responsibility for making sure the water supply is maintained is with the owner, or collective owners.

You should find out the answers to the following questions to make sure your water supply is safe to drink:

  • Who is responsible for the upkeep and maintenance of the supply, particularly any treatment equipment?
  • Where is the water taken from and is anything necessary to protect this source?
  • How does the water get into your property and do the pipes need maintaining?
  • Is the water treated and is the equipment in good working order and regularly maintained?

All parts of the supply should be regularly inspected, including the catchment area. The inspection should include checking for damage, or for the presence of anything which may affect the water quality.

When to get your supply treated

If your water supply is contaminated this should be put right by the owner(s) as soon as possible. You should boil the water before using, or use bottled water instead, if your supply has micro-organism contamination.

If you think your water supply is at risk of becoming contaminated, the owner(s) should have a water treatment system installed. If you share your supply with other properties it is possible to have the treatment within the catchment area rather than in each house. 

If you have lived at your property for many years you may have developed a level of immunity to some of the bacteriological contaminates in your supply. However treatment should still be carried out because any visitors may not have immunity, especially very young children.

Water quality testing and treatment advice

A treatment equipment supplier will be able to discuss treatment options with you, although they may need to test the supply in order to provide accurate advice.

If you are not sure, or are concerned that your water supply is contaminated, you can contact our Environmental Protection team for advice or to arrange a test.

If you need a test, an officer will let you know how much this will cost and you can pay this fee online. 

Pay now

Once it’s ready, the result of your test will be available to view online through MyAccount. The team can give you advice on the results of the test and what treatment types are available.

Fees and charges

Private water supplies
Fees and charges
Type Fee
Initial risk assessment (Regulation 8 and 9 supplies) £500
Initial risk assessment (Regulation 10 and 11 supplies) £300
Sampling visit £100
Bacterial and chemical suites* (1 to 15)
For example, the basic bacterial suite (named 'WCBCPWS8') costs £25 and includes: E.coli, enterococci, turbidity, conductivity and hydrogen ion concentration (pH)
£25 - £173.85
Investigation £100
Auditing risk assessments (minimum for first hour) £50

*We currently provide 15 different test suites of various bacterial and/or chemical parameters to cover site specific geographical conditions. The price range varies depending on a request for testing for additional specific parameters or requirements based on the site's history and previous test results.

Sample analysis
Type Fee
Regulation 10 and 11 domestic supplies £25
Check monitoring of commercial supplies taken during monitoring for group A (microbiological) parameters up to £118.17*
Audit of commercial supplies taken during monitoring for group B (chemical) parameters Up to £600
Should fails be recorded then the fees for re-testing chemical parameters of concern can be levied on the owner up to this amount
Re-test after a fail No fee
Subsequent re-tests after notification of a 2nd fail £25
Risk assessment review/updates (due every five years) £130 (maximum fee)

* If fails are recorded then the fees for re-testing microbiological parameters of concern can be levied on the owner up to this amount.

Environmental searches
Time duration Fee
Per hour or part hour No fee currently

Contact our Environmental Protection team to check site specific fees and to request testing.

Maintaining the water supply

If you supply water as part of a business

You have a duty of care if you run a business that uses a private water supply. You are required to have your supply assessed annually and you should contact our Environmental Protection team to discuss this. 

If you think your water may be unfit for consumption, you should arrange for testing as soon as possible. In the meantime you must advise your customers to use bottled water or to boil their water before using.

If you are on a shared supply with other properties

Shared water supplies require evaluating on a five yearly basis and you should contact our Environmental Protection team to discuss this. 

For shared supplies there should be a clear written agreement between all users. At a minimum this agreement should set out:

  • Who is responsible for the supply (such as one person or everybody equally)
  • The right of access to the water supply for all users
  • How will repairs be paid for
  • Any running costs and how these are paid for
  • The nominated contact for the supply
  • A contingency plan in case the water is unavailable or unfit for consumption

Preventing contamination in specific types of water catchments

Supplies from underground sources (boreholes, springs and wells)

Underground sources are considered the safer option for private water supplies. The catchment area should be checked to prevent surface water from getting into your supply and to determine if any minerals are present. 

Supplies from surface water (rivers, streams, lakes and ponds)

These are regarded as the more risky types of private water supply. There is particular risk when the water catchment is near to livestock because land based contaminants (for example from farming activity) can be washed into the supply when it rains. 

If possible, rainwater runoff should be diverted away from the catchment area. If suitable a fence could be built around the supply to prevent animals from gaining access. 

Connecting to mains water

If you decide that you no longer wish to use your private water supply, ask your local water company about connecting to the mains supply. You may have to pay all the costs involved and you should discuss this with the water company.

Wrexham is served by the following water companies:

Related links

Contact us about private water supplies

Email: healthandhousing@wrexham.gov.uk