A spot in Powys has earned the unfortunate distinction of having the highest number of sewage discharges in Wales, with eight months’ worth of spills in 2023.

Llanbrynmair Central Sewer Overflow was ranked as having the highest number of days of sewage spilled into its river, with a total duration of 8 months and 10 days over the last 12 months.

In March, figures for water overflows were released, showing Llanbrynmair ranked highest for total hours of spills, clocking in at 5,811 hours.

Llanbrynmair councillor Gary Mitchell said: “Not the sort of leaderboard that any community wants to be top of.

“That’s why I and Cllr Elwyn Vaughan have been working with Plaid Cymru and Llanbrynmair Community Council to press Welsh Water to clean up its act.


“There are only 730 hours in an average month, therefore the figures indicate that the treatments works in Llanbrynmair have been spilling over into the River Laen for more than 240 full days during last year, releasing untreated raw sewerage into our environment whilst doing so. It’s simply not good enough.

“I held several on-line meetings with their senior team in Wales and arranged a site visit with them and fellow councillors last year at the site to learn more, first-hand, about the issues creating these headline figures.

“I’m pleased to say that due to some of this pressure Dwr Cymru have agreed to spend some re-medial monies on improving the site and allowing them to carry out further monitoring.

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“However, I have still not seen the environmental impact data they have collated and will continue to press them to share this information.”

While the spills are not 100 percent sewage, as the figures also include overflows from surface water as a result of increased rainfall. Heavy storms but the sewage system under pressure, leading to rainwater filling up the system and causing an overflow. However, this means the water spilled into rivers will contain sewage.

A spokesperson for Dwr Cymru said: “We are aware of the high number of spills coming from the overflow at Llanbrynmair and we have already been working in the area investigating the cause.

“Early indications are that unusually high levels of groundwater are entering our system which then spills out through our storm overflow.

"This in turn records a high spill number for the area. We appreciate the high number may cause some concern locally but we can assure people that once our investigations are complete we will then be able to identify the best way of mitigating the situation. 

“We are keeping Natural Resources Wales updated on progress with our work and we would like to thank the local community for bearing with us during this time.

“We take the issue of spills from storm overflows extremely seriously with around £140 million being invested in improving storm overflows between 2020 and 2025, and a further £420 million planned for 2025 to 2030.”