Welsh Water criticised for high incidence of serious pollution incidents

Martin Shipton

Welsh Water has been strongly criticised for having one of the worst records on serious pollution in England and Wales.

Natural Resources Wales’ annual environmental assessment of the water company’s performance in 2025 states: “There were eight serious incidents in 2025 that had a significant (Category 2) environmental impact, and one that had a major environmental impact (Category 1). To achieve green in this metric they must achieve zero incidents, where amber equals one incident. The incidents were linked to a range of assets, including water distribution mains, rising mains, foul sewers and sewage pumping stations. Four of the nine were linked to a series of bursts along one rising main in south Wales.

“For the fourth year running, Welsh Water continues to hold red status for serious pollution incidents, preventing promotion to a higher star rating. This is particularly concerning given the continued increase in serious sewerage pollution incidents, with 2025 representing the company’s poorest performance on record.”

A joint report from the regulators Ofwat, the Environment Agency and Natural Resources Wales said in relation to Welsh Water: “Wider environmental performance requires improvement. The company has a high number of pollution incidents, especially those of a serious nature. Progress has been made in self-reporting of incidents and this needs to be maintained. It should prioritise measures to minimise incident occurrence and the timely reporting of incidents to facilitate early intervention and avoid escalation.”

Other criticisms of Welsh Water include leakage of 156.4 litres per property per day, above the industry average of 104.5 litres. Total leakage nevertheless fell by 0.39% compared with the previous year.

Household consumption is also above the industry average, at 150.6 litres per person per day compared with 137.3 litres.

Rhodri Williams has just stepped down as chair of the Consumer Council for Water after seven years.

Delivery

He told Nation.Cymru: “People will judge Welsh Water by its performance. It has an ambitious investment programme aimed at improving, but it’s the delivery that will count.

“For years the company was reluctant to increase its bills, which meant that the 30% rise that has been imposed recently came as a shock. Welsh Water has tried to blame the regulator, Ofwat, which sets a maximum charge, but the company has never appealed against its decisions. That means that Welsh Water must take responsibility for its performance failures.”

A Welsh Water spokesperson said: “We recognise that our performance needs to improve, particularly on serious pollution, and we are sorry for the harm these incidents cause.

“Four serious pollution incidents in 2025 were linked to the Marlas main, which we are replacing through a £30m investment to address repeated failures and reduce the risk of further incidents. This does not diminish the impact of those incidents, but demonstrates the targeted action we are taking to tackle their causes.

“Although total leakage fell slightly compared with the previous year, it remains too high. We are focused on finding and repairing leaks and improving the resilience of our network.

“Household water consumption is also above the industry average. We are supporting customers to use less water through practical advice and water-efficiency measures, alongside our responsibility to reduce leakage.

“Our priority is to turn investment and operational improvements into sustained, measurable progress for customers and the environment.”