Water companies told to install monitors on 7,000 sewage pipes

Water companies in England and Wales will be required to install monitors on an additional 7,000 emergency overflow pipes used to dump sewage into the nation’s waterways, the environmental watchdog has said.

The emergency pipes, which have so far escaped monitoring, are separate to thousands of combined sewage overflow pipes, which are only meant to release sewage during extreme rainfall and are designed to prevent flooding.

All of these had event duration monitors installed by the end of last year, the Environment Agency said.

By contrast the emergency overflow pipes are meant to operate only in urgent circumstances such as power outages and failures that are not “due to the act or default of the water company”, the EA said. Water companies will be forced to install monitors on them in stages from the beginning of next year initially targeting designated bathing and shellfish waters, as well as chalk rivers.

Helen Wakeham, director of water transformation at the Environment Agency, said it wanted “complete transparency on discharges of sewage to our water environment”.

“While 100 per cent of storm overflows in England are already monitored, we are also requiring companies to monitor all emergency overflows from 2025, not just those which impact on shellfish waters. As we transform the way we regulate the industry, this high level of transparency is critical,” she added.

The requirement since 2015 for water companies to install event duration monitors has transformed public awareness of sewage discharges, with some companies including Thames Water providing real-time maps of outflows. 

There has been a wave of protests as campaigners including Windrush Against Sewage Pollution revealed that combined sewage overflows were dumping sewage even in dry weather.

However, water regulator Ofwat said last year that about one in six monitors installed on the CSOs worked less than 90 per cent of the time in 2022. An additional issue is that the EDMs record only when the outflows occur and not the volume released.

Just 16 per cent of waterways in England and Wales meet minimum EU standards for ecological status and none meet the standards for chemicals, according to EA data.

Although companies often blame unpredictable weather and climate change for causing more frequent untreated sewage overflows, a study by Imperial College London last year found that by far the biggest problem was insufficient capacity at wastewater treatment plants, which meant they were releasing sewage into waterways even during dry periods.

The regulator is now investigating six water companies over concerns that they might have breached sewage regulation. The EA is also conducting its largest ever criminal investigation into potential widespread non-compliance by water and sewerage companies at more than 2,200 sewage treatment works.

Water UK, which represents the industry, said: “Water companies are committed to robust monitoring of storm overflows across England and Wales.

“Due in part to their operating outdoors and in all weather conditions, some monitors will occasionally be temporarily out of action while maintenance is under way. This has improved, and the regulator has taken tough new powers to ensure the highest standards.”