​Why do water companies pump raw sewage into our rivers and seas?

By Bob Fear

​Why do water companies pump raw sewage into our rivers and seas?

Water firms in England and Wales have been illegally dumping raw sewage into rivers and the sea on a regular basis, according to recent investigations and inquiries. Underfunding and a failure to enforce water quality has been blamed. We look into how our waterways have become so seriously damaged.

Water companies are allowed to pump untreated sewage into the UK’s rivers and surrounding seas when too much rainfall threatens the capacity of their water tanks. This prevents sewage from backing up into our streets and homes. The water firms should screen their raw sewage before they discharge it.

During heavy rain or a storm, the amount of water flowing into your local wastewater treatment works might be more than they can properly treat. When this happens, the water companies divert untreated water into storm tanks, if they have enough of them. After a storm subsides, the water in the storm tanks should then be returned and treated as normal.

However, if rain is particularly heavy or a storm continues for a while then, according to Ofwat (the regulator of the privatised water companies), the water firms are allowed to ‘release the extra incoming rainwater and diluted wastewater into the environment, normally after partial treatment by settlement by storm tanks or through storm overflows into a river or sea’. The permits that allow the water companies to do this are enforced by the UK government’s Environment Agency. These permits specify how much waste water must be treated before the firms can then pump untreated sewage into our rivers and seas.

The Environment Agency revealed that water companies in England dumped raw sewage into rivers over 400,000 times in 2020. This means that untreated water contaminated with human waste entered our waterways for more than three million hours over the year. The agency said that these overflows were ‘a necessary part of the existing sewerage system’ and that wet wipes are the main cause of blockages in the sewers. If we stop flushing wet wipes and pouring fat and grease down the drain we could help prevent most sewer blockages, they suggested.

In 2021, a BBC investigation found that most water companies in England and Wales were illegally dumping raw sewage into our rivers. Eight of the eleven firms were breaching their permits by releasing untreated wastewater before treating the amount they are supposed to. Welsh Water illegally dumped raw sewage for 12 consecutive days in 2020, while one Thames Water site breached its permit on 43 days and another released sewage almost continuously for three months.

While Ofwat and the Environment Agency were investigating these breaches, in early 2022 the Environmental Audit Committee (a cross-party group of MPs monitoring the environmental impact of all government departments) claimed that untreated wastewater was regularly being illegally dumped. Seven water companies pumped raw sewage onto our coast more than 3,000 times from 2017 to 2021. The committee complained that self-monitoring by the industry had led to unacceptably high unpermitted sewage discharges, urging regulators and water companies to ‘get a grip’.

The chairman of the Environmental Audit Committee, Philip Dunne, said: ‘Our inquiry has uncovered multiple failures in the monitoring, governance and enforcement on water quality. For too long, the Government regulators and the water industry have allowed a Victorian sewerage system to buckle under increasing pressure.’

‘The decision by water companies and the government to view rivers as places that can absorb pollution has turned these precious watercourses into all but an open sewer,’ said Surfers Against Sewage, a national marine conservation and campaigning charity, in their 2021 Water Quality Report. ‘This sorry state of affairs is a result of weakened legislation and a defunded regulator, which has allowed the monolithic water industry to operate with near impunity – self-regulating and reporting pollution when it feels like it.’

The trade association representing the water companies, Water UK, has acknowledged the ‘urgent need for action to tackle the harm caused to the environment by overflows’. The Environment Agency responded by saying ‘we will not hesitate to pursue the water companies concerned, and take appropriate action’.

In the meantime, the Environment Act of 2021 now legally binds all water companies to provide transparent, year-round data on their sewage discharges. The Rivers Trust, an environmental charity dedicated to the conservation of our rivers, has created an online map <https://www.theriverstrust.org/key-issues/sewage-in-rivers> which shows exactly where the sewerage network discharges and overflows into rivers. Also, Surfers Against Sewage has created the Safer Seas and Rivers Service <https://www.sas.org.uk/map/>, an app which tracks sewage overflows and pollution risk forecasts, monitoring water quality at over 400 locations around our rivers and coastlines.



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