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Private water supplies

What is a private water supply and what to do if there is a problem with your supply

What is a private water supply?

A private water supply (PWS) is a supply that isn’t normally connected to the water companies’ public mains. The source can be from a well, borehole, spring, stream, river, lake or pond.  The private supply can be for commercial and/or domestic use so the water should be safe because it could be used for drinking, cooking, food preparation and washing. Water used for just toilet flushing also comes under the requirements.

If the supply is not appropriately maintained or treated, it could become contaminated with bacteria or chemicals which can cause illness. To ensure that illness doesn’t occur, a supply should meet the quality standards that are prescribed in the regulations.

Classifications of private water supplies

There are different classifications of PWS systems. The classification depends on the size of the system and the amount of people that use the system. The classification alters the frequency of risk assessments and sampling.

  • Regulation 8 - private distribution system – water taken from a public main which is further distributed by a person other than the water undertaker.
  • Regulation 9 - “Large domestic supplies” (more than 10 cubic metres [m3] used per day or over 50 people) and all “Commercial supplies”. A risk assessment should be completed at least once every five years and sampling at least once per year.
  • Regulation 10 (other private supplies):
    • “Small  Domestic supplies” (less than 10 m3 used per day or less than 50 people but supplying more than one property, where the occupants are owner occupiers) - A risk assessment should be done once every five years and sampling at least once every five years.
    • “Single private dwelling” (not used for a commercial activity, normally where the property is not rented) – Sampling and risk assessment will be done only if asked. This type of supply should contain only one property.

Our involvement

We're involved because:

  • legislation requires that water used for human consumption is safe. Where it is not, we are duty bound to serve a notice to require the necessary improvements
  • we're required to carry out risk assessments and sampling on these supplies, with the exception of single domestic dwellings (unless this is requested)

Problems with your water supply

We will:

  • investigate - what's the problem and why
  • keep you informed if the supply becomes a potential danger to your health
  • give you advice, which will help to minimise any potential danger
  • work with other professional bodies (for example, UK Health
    Security Agency) to seek further advice about any potential danger

If we find that your supply requires some improvements, we'll work with you to prevent any further danger to human health. If necessary, we can take formal action, in the form of legal notices, to ensure works are carried out. We can also make reasonable charges to cover the costs for carrying out any required works.

Fees for work

We'll confirm the price with you for any works, but the following are example charges:

Fees for private water supplies
Type of supply Time taken (includes 1 hour average travel time) Risk assessment (£76 ph) Sampling (one sample) – second sample £36.20 plus analysis Authorisation
(application for permission to breach standard temporarily)
Regulation 10 - (Single owner occupied) 4 hours £220.80 £76 plus analysis cost £110.00
Reg 10 - Small supplies 7 hours £438.00 £76 plus analysis cost £110.00
Regulation 8 & 9 - Large/commercial/private distribution system 11 hours £438.00 £76 plus analysis cost £110.00

Sampling fees consist of two parts;

  • Part 1: the cost of the laboratory analysis plus 
  • Part 2: the cost to the council of undertaking the sample
Sampling and laboratory fees
  Part 1 Part 2
  Council costs per visit Council costs for hour thereafter (min 15 mins)
Regulation 8, 9, 10 (small and single) Laboratory Analysis £76.00 £36.20
No access or late cancellation fee of booked sample (less than 24h notice) N/A £25.00 £36.20
Investigation carried out in the event of test failure, but can be substituted by risk assessment  Where samples are required; Laboratory Analysis £76.00 £36.20

The current cost of an average Regulation 9 sample in 2024/25 will be approximately £316 which includes the Council and current Laboratory costs.

Please note that the overall cost may increase should the Laboratory increase costs. This cost does not include any pesticides. Pesticides will be added where a risk assessment or investigation has identified a need.


There should be a regular, preventive maintenance programme, which enables early identification of problems. When there is a problem with the supply and it cannot be used, there should be contingency arrangements for planned and unplanned supply outages such as drought or failure of power supply.

Further information

For more information on the management and treatment of private water supplies, the Drinking Water Inspectorate (DWI) has useful information on their website please visit the DWI Private Water Supplies in England and Wales page. The DWI has also produced a useful manual for treatment of small water supplies. This looks at how to maintain the system together with water treatment options Manual on Treatment for Small Water Supply Systems - Drinking Water Inspectorate (DWI.GOV.UK).

Contact us 

If you would like to request a water sample or a risk assessment, please contact us.