Products supplied and installed within the public distribution network of Dŵr Cymru Welsh Water between 12 June 2024 and 27 August 2024 did not hold valid approval during that period, the Drinking Water Inspectorate has reported. The finding came from a routine regulation 31 compliance assessment undertaken in relation to materials intended for use in a planned capital scheme1.
The event was the most significant notified to the Inspectorate in Wales in 2025, with an Event Risk Index (ERI) score of 5,299. By comparison, the highest scoring event in 2024 had an ERI of 240. The Inspectorate says regulation 31 events can attract large ERI scores because of the size of the potentially affected population and the duration of the event, which may extend over a considerable period while unapproved products remain in situ before they are identified and removed1. The table of top scoring events records the case as "Use of unapproved materials/products", classified 3 (Significant), with the final event assessment "Prosecution considered" and an ERI score of 5,298.6821.
The company confirmed that neither the product composition nor the instructions for use had changed between the lapse in approval and subsequent reapproval, and a risk assessment it carried out concluded that the associated risk to water quality was low. The company was initially unable to determine the exact specifications or installation locations of the fittings, but has since carried out retrospective analysis and determined that a population of 1,123,195 were impacted out of a total company population of 3,093,1581.
The Inspectorate reports that the company has acknowledged the installation of unapproved products occurred. While the company maintains that the risk to water quality was low, the Inspectorate says it was unable to fully substantiate this assessment because of the absence of detailed records relating to fitting types and precise installation locations. Recommendations were given requiring a critical review of procedures concerning record keeping, regulation 31 compliance assurance, and the methodology used for surface area calculations to demonstrate exemplar status1.
"Companies should ensure that systems are in place to prevent the use of products that do not have regulation 31 approval, the critical point in time being when water goes into supply."
The report records 65 events notified to the Inspectorate in 2025. Thirty-two of these were single-property incidents, 16 of which related to consumers' distribution systems and were therefore outside the control of the water company. The second highest ERI score was recorded by Albion Eco, at 657, for a loss of supply event following an upstream mains burst; the Inspectorate notes that the small supplied population of 180 meant the score was proportionately higher than it would have been for a similar event affecting an incumbent company1.
| Company | Event | Classification | Event assessment | ERI score |
|---|---|---|---|---|
| DWR | Regulation 31 Approval | 3 (Significant) | Prosecution considered | 5,298.682 |
| ALE | Broughton Mains | 3 (Significant) | Recommendations made | 657 |
| DWR | Aston Burst | 3 (Significant) | Enforcement-legal instrument | 245.807 |
| DWR | Bryn Cowlyd WTW Loss of Supply | 4 (Serious) | Recommendations made | 164.335 |
Source: Drinking Water Inspectorate, top 10 scoring events notified in 20251.
Why it matters for households
The affected population of 1,123,195 is the number the company determined, out of a total company population of 3,093,158, for products installed in the public distribution network over that period1. The Inspectorate's account does not identify which areas or properties received water through the fittings concerned, and this has not been reported. The company's position, as recorded by the Inspectorate, is that the risk to water quality was low, based on unchanged product composition and instructions for use and on surface area calculations for typical fittings1. The Inspectorate accepted that the company acknowledged the installation but states that the low-risk assessment could not be fully substantiated because detailed records of fitting types and locations were absent1. The event assessment recorded is "Prosecution considered"1. No outcome of any prosecution has been reported in the account.
Households that store water for outages can find general guidance in the site's water hub and in how much drinking water to store per person.
What happens next
The Inspectorate reports that recommendations were given requiring a critical review of procedures concerning record keeping, regulation 31 compliance assurance, and the methodology used for surface area calculations to demonstrate exemplar status1. No timetable for that review, and no further regulatory step beyond the recorded assessment, has been reported.
