More Than 800,000 Hours of Sewage Discharged Into Welsh Waters in 2025

More than 800,000 hours of sewage was discharged into rivers, lakes and seas across Wales last year, according to new figures.

The charity Surfers Against Sewage, which analysed data from Welsh water companies, said there were more than 100,000 sewage discharges in 2025. That equates to more than one discharge every five minutes.

Although the total was down from the previous year, when more than 970,000 hours of sewage were discharged, environmental groups said significant concerns remained over water quality, investment and enforcement.

Sewage discharges in Wales fall but remain high

Natural Resources Wales (NRW) said it had strengthened its regulatory approach through increased oversight and tougher guidance. The regulator is also overseeing a “significant environmental investment programme” by water companies.

Surfers Against Sewage said the dry weather last summer contributed to the decline in sewage discharges. However, the charity said a lack of investment and enforcement continued to be an issue.

Sewage-related illness reports in Wales

In its annual review, the charity said it had received 992 reports of sewage-related illness in Wales since 2019, including 215 reports in 2025.

These illness reports resulted in more than 2,200 days of absence, according to the review.

35,669 hours of sewage discharged near Welsh bathing waters

The charity said sewage was discharged into designated bathing areas in Wales for a total of 35,669 hours during the year.

At Llyn Padarn in Gwynedd, sewage discharge lasted for 1,614 hours, despite the lake’s designated bathing water being classified as excellent for water quality.

Environmental and health concerns

Regulations allow limited sewage discharges during periods of excessive rain. However, environmental groups remain concerned that the levels pose a threat to wildlife and create health risks for swimmers.