Private water supplies

Private drinking water supplies

A Private Water Supply is a water supply which is not provided by a water company. These supplies may be a well, borehole, spring, stream, river, lake or pond.

Under the Water Industry Act 1991, the local authority has a duty to monitor all PWS in their area. This includes sampling and risk assessing the supply.

The Private Water Supplies ( England) ( Amendment ) Regulations 2018 divide private water supplies into 3 categories for monitoring purposes. These are:

  • Commercial or large supplies (more than 10 cubic meters of water/day or supplying 50 people or more)
  • Small supplies (domestic use only) (less than 10 cubic meters of water/day or under 50 people using the supply)
  • Single Dwellings (only one single domestic dwelling uses the water)

Commercial supplies include food preparation/production, care homes, holiday homes, B&Bs, caravan, campsites and tenanted properties. Domestic purposes include drinking, cooking and washing.

What are the main differences between the categories?


The main differences are the size of the supply, the frequency of sampling and the number of parameters that are sampled for.

Commercial/large supplies – must be sampled at least once a year and are subject to most tests.

Small supplies – as a minimum these supplies must be sampled at least once every 5 years.

All supplies are risk assessed every 5 years.

Single Dwellings – there is no requirement to sample or risk assess these supplies. The local authority will only risk assess and sample at the request of the owner/occupier, who is responsible for charges

I have a private water supply. Should I notify the local authority?


Yes. The Private Water Supply Regulations 2016 apply to all PWS and require Local Authorities to report annually to the Drinking Water Inspectorate of all supplies. New supplies or bringing an old supply back into use are required to be risk assessed by the Local Authority before doing so.

If you require further information, contact the Food Safety Team.



The regulations allow us to recover the costs of carrying out a risk assessment, sampling and analysis. For further information on charges relating to private water supplies contact Environmental Health Food Safety Team.


Contact details

Food Safety and Infectious Disease
The Royal Borough of Kensington and Chelsea
Council Offices, 37 Pembroke Road, London, W8 6PW | Tel: 0207 361 3002


Visit the Private Water Supplies website for further information

Last updated: 26 August 2022