Local Authorities

Sampling of Private Water Supplies

Local Authorities in England will note that the 2018 amendment regulations require that “A local authority must secure that a person accredited by the United Kingdom Accreditation Service checks from time to time the local authority’s compliance with the appropriate requirements,  In addition ”the local authority must demonstrate compliance with the following standard—

(a) as regards any such activity, other than analysing samples, on or after 11th July 2020, European standard EN ISO/IEC 17024 entitled “Conformity Assessment. General requirements for bodies operating certification of persons”

Furthermore that “the person taking the sample is doing so in accordance with a system of quality control to an appropriate standard.”  This includes ensuring that “the sample is kept at such a temperature and in such conditions as will secure that there is no material alteration of the concentration or value for the measurement or observation of which the sample is intended.”

The same requirements apply in Wales as per the Private Water Supplies (Wales) Regulations 2017, which came into force in November 2017.

  To assist Local Authorities comply with these requirements, please note that Inspectorate has facilitated the implementation of an ISO 17024 scheme (PDF 126KB) for samplers of private water supplies in collaboration with UKAS, the basis of which is a standard sampling manual . This is currently being trialed by some local authorities and is due for completion at the end of 2018. The Sampling Procedures Manual also covers the international standard ISO 5667-5 entitled “Water quality. Sampling. Guidance on treatment of drinking water from treatment works and piped distribution systems” and the European standard EN ISO 19458 entitled “Water Quality – Sampling for microbiological analysis”.  Further detail will follow in due course.  Meantime Local Authorities need take no further action to ensure they comply with these regulatory requirements, but should continue to follow the Sampling Procedures Manual on the DWI website in readiness for this certification.

The amendment regulations for England can be found here:https://www.legislation.gov.uk/uksi/2018/707/regulation/2/made
The regulations for wales can be found here: https://www.legislation.gov.uk/wsi/2017/1041/contents/made
A sampling manual, which will form the basis of  the ISO 1704 scheme manual can be found here: http://www.dwi.gov.uk/private-water-supply/regs-guidance/Guidance/sampling/pws-sampling-procedures.pdf

Local Authorities are advised to familiarise themselves with these procedures.

Statutory Duties

Section 77 of the Water Industry Act 1991 requires a local authority to keep itself informed about the wholesomeness and sufficiency of every private water supply within its area. Each local authority achieves this by conducting its statutory duties which includes; risk assessments, investigations, authorisations and monitoring (sampling and analysis). The Regulations also make provisions for local authorities to charge fees to the relevant person(s) for conducting these duties.

If through these duties a local authority deems a private water supply to be unwholesome and/or insufficient then it has the power under the Regulations to serve notices on the supply in order to mitigate against these risks

Local authorities are under a statutory duty to provide reporting information relating to private water supplies to the Secretary of State and Welsh Ministers. This submission of data is due on 31 January of every year, for records relating to supplies in their area during the previous calendar year.

Case Studies

Given the varying nature and condition of private water supplies available the Inspectorate has made available a number of different Case Studies in order to provide additional guidance for local authorities.


Page reviewed: 11 October 2018
Page modified: 19 February 2019

Drinking Water Inspectorate