Welsh Water has admitted to spilling untreated sewage near a rare dolphin habitat for at least a decade.
A BBC investigation found the water company had been illegally discharging untreated wastewater at dozens of sewage plants, often for years at a time.
The organisation has promised to tackle the problems after viewing the analysis, which it did not dispute.
Water companies across England and Wales frequently discharge sewage into rivers and seas. In England, sewage was spilled via storm overflows more than 300,000 times last year.
Peter Hammond, a former UCL professor who campaigns for Windrush Against Sewage, collated the data, which shows Welsh Water was discharging sewage before it reached its stipulated overflow level, which means it should have been treating it, but was not. He asked the Welsh Rivers Trust, as well as local anglers, for suggestions for outflows to look at.
Sewage systems overflow during periods of heavy rain, and companies are allowed to discharge when they reach a certain level to prevent waste backing up into homes, but not before.
The data, from 11 Welsh sewage plants, found that 10 released untreated waste before their stipulated overflow level had been reached. The worst-performing plant was Cardigan, which spilled for more than 200 days a year from 2019-22, and it almost never treated the sewage it was supposed to. The treatment plant spills into the Teifi estuary, where there is one of Europe’s largest populations of bottlenose dolphins. Welsh Water said in response that the nearby Poppit Sands beach had water rated “excellent”.
Hammond told the Guardian the dumping of sewage in the rare dolphin habitat “really upset me”. He added: “There are dolphins only in two places regularly in Wales and Scotland. And they’re dumping on one of them.”
This pattern is repeated in England. Earlier this year the high court heard that in 2022 52% of the raw sewage discharges from the 14,000 storm overflows that were monitored spilled more than 10 times. Eleven per cent discharged raw sewage more than 60 times. As such they had been in breach of the law – the urban wastewater (England and Wales) regulations 1994. The environmental watchdog in England recently declared that ministers might have broken the law over sewage dumping.
Welsh Water told the BBC it has between 40 and 50 wastewater treatment plants currently operating in breach of their permits, and that decisions on improvements were taken with customer bills in mind.
A spokesperson added: “Regarding Cardigan works specifically, we had already identified the issue there being linked to saltwater entering the works, which impacts the treatment process. We reported this to Natural Resources Wales (NRW) and agreed to undertake investment to improve the situation.” They are now investing a further £20m to ensure compliance with their discharge permit, and have disclosed the issues to NRW.
Hammond responded: “In the case of Cardigan, it’s been known for 10 years. And obviously, Welsh Water have not got to grips with it. You know, they say they’ve tried various solutions, but nothing’s worked.”
He said he believes they installed their current system in 2004 and have known about the problems for at least 10 years. “So you would have thought that by now, they would have put the money in.”
Huwel Manley, NRW’s head of operations for south-west Wales, told the BBC: “We have prosecuted Welsh Water on a number of instances for pollution events, just not for low flow spills as is the case here.
“But we are working with trying to set national guidance along with England so that we have a more standardised approach as to how and when we take that prosecution route.”
A Welsh Water spokesperson said: “We have over 5,000 environmental permits as Wales has some of the largest numbers of treatment works, pumping stations and storm overflows in the UK. We are continually monitoring and when we find issues, we share this data with regulators, investigate and deliver improvements. We are investing around £1m a day in improving our services.
“We always aim to resolve any issues as quickly as possible, to limit any impact for both the environment and our customers.”
