Skip to main content

Information on the level of poly and perfluoroalkyl substances in Welsh drinking water supplies.

Read details on this page

First published:
13 April 2022
Last updated:


Annex A , file type: PDF, file size: 45 KB

45 KB
If you need a more accessible version of this document please email Please tell us the format you need. If you use assistive technology please tell us what this is.


8 April 2022

Dear             ,

Request for Information – PFAs in drinking water (16201)

Thank you for your request of 24 March 2022.

You have asked for the following:

  1. Information the Welsh Government holds on the level of Poly- and perfluoroalkyl substances (PFAS) in Welsh drinking water supplies; and
  1. A time series of that data over the last 5 or 10 years that it's been reported.

Our response

Following a trawl of our paper and electronic records, I have established that there is some limited information you require held by the Welsh Government in relation to point a) above.

On 1 October 2021, the Drinking Water Inspectorate (DWI) requested all water companies in England and Wales to collect data on 43 PFAS compounds in raw water sources in high risk areas. The letter can be accessed at Information-Letter-PFAS-Monitoring.pdf ( These finding have not identified any significant risks to drinking water quality. DCWW found only one raw water sample which was above the required Level of Detection (LoD). Samples from treated water showed no LoD. Please see Annex A for the relevant data presented by DCWW.

The Welsh Government holds no further data on PFAS levels in drinking water in Wales, including information requested under point b).

I advise you that you contact the water companies directly for the data you require. Information on how a request can be submitted is available at the companies’ website:

Dwr Cymru Welsh Water.

Hafren Dyfrdwy

Next steps

If you are dissatisfied with the Welsh Government’s handling of your request, you can ask for an internal review within 40 working days of the date of this response. Requests for an internal review should be addressed to the Welsh Government’s Freedom of Information Officer at:

Information Rights Unit, 
Welsh Government,
Cathays Park, 
CF10 3NQ 
or Email:

Please remember to quote the ATISN reference number above.

You also have the right to complain to the Information Commissioner. The Information Commissioner can be contacted at:

Information Commissioner’s Office, 
Wycliffe House, 
Water Lane, 

However, please note that the Commissioner will not normally investigate a complaint until it has been through our own internal review process.

Yours sincerely