When we flush the loo or drain the kitchen sink, that wastewater enters the sewerage system where it is sent to be treated and disposed of responsibly. At least, that is the service we should be able to expect.

A number of high profile incidents have raised concerns around the discharge of sewage into our rivers, streams, lakes and seas. So what is going on?

Below we have put together answers to some frequently asked questions.

Are water and wastewater companies allowed to put sewage in rivers and streams?

Yes. In certain circumstances, water and wastewater companies are allowed to discharge sewage into rivers and other bodies of water such as streams, lakes and coastal water. This is done via Storm Overflows, which redirect excess wastewater from sewage works and sewers to nearby bodies of water.

Why are companies allowed to do this?

During very heavy rainfall, or when a blockage occurs, the sewerage system can become overwhelmed, creating the risk of:

  • Sewage flooding people’s homes, businesses or streets. Or;
  • Sewage treatment works being overloaded.

As a last resort, Storm Overflows can help to prevent these things from happening, by releasing some of the excess rain and wastewater from the sewerage system. Their use beyond this should never be tolerated.

How often do companies do this?

When originally built, Storm Overflows were only intended to be used in exceptional circumstances. However, recent monitoring has uncovered that storm overflows are being used far more frequently than was originally intended, with the risk of causing harm to the environment and quality of life for local communities.

This map by the Rivers Trust gives an indication of where and how often the sewerage network discharges treated and untreated wastewater into rivers and other watercourses.

Why is this happening so much?

There are a number of possible reasons why water and wastewater companies are using Storm Overflows more often than was intended. Some of these are to do with changes that water and wastewater companies have limited control over, such as climate change, which is causing more frequent and intense  rainstorms, and the loss of green permeable spaces, which help to absorb rainwater. This means it is important for water and wastewater companies to plan ahead to be able to cope with these changes.

However, a number of high profile incidents have raised concerns about the potential misuse of Storm Overflows by water and wastewater companies.

Some companies have been fined for inappropriately releasing untreated sewage into the environment.

Why didn’t we know about this before?

In 2016, only 900 of the 15,000 storm overflows in England had devices fitted to alert water companies to when sewage was spilling into rivers and streams. There are now over 12,000 devices fitted, so companies and the Environment Agency have a much better idea of the scale of the problem. In Wales, a higher proportion of overflows are monitored; as of 2021 almost 100% of the over 2,000 overflows in the country are monitored.

Water companies and the environmental regulators will need to be using this information to identify where storm overflows are harming the environment and decide how best to stop this happening.

What are Ofwat and the Environment Agency Investigating?

In November 2021, Ofwat and the Environment Agency (EA) launched an investigation into sewage treatment works after a number of water companies admitted to them that they might be releasing unpermitted sewage discharges into rivers and streams. This investigation is looking at both English and Welsh sewage treatment works.

Should current or future investigations lead to prosecutions, CCW would want to see fines used locally to repair the environmental harm caused by the inappropriate use of storm overflows. In November 2021, CCW wrote to Ofwat and the EA seeking further information for customers. You can read both these letters here.

In February 2022, Ofwat provided an update on their progress in this investigation: “We have now completed an initial assessment of the summary information we requested from wastewater companies, returned to us in December. It is helping us to start to build a picture of where companies may not be managing their wastewater treatment works in line with their environmental requirements, and the possible causes of that. The companies’ responses also set out where and how they are taking steps to put right any problems they have found and to rebuild their customers’ trust on this issue. The companies’ responses have varied in their level of detail and evidence, and in how well-advanced their plans are to put things right.”

What impact does sewage pollution have on the environment?

Sewage pollution can not only make our rivers and beaches less pleasant, and less safe, for visitors and local communities, it can also damage ecosystems, killing wildlife and threatening biodiversity. Overflows during a storm tend to be heavily diluted and so tend to have a lower environmental impact than overflows during dry weather.

Are rivers and seas safe to play and swim in?

It is important to consider all the possible risks before entering a river or other body of water – cleanliness being one. The Environment Agency tests and publishes the water quality of 400 designated bathing waters between May and September every year. You can find their list of designated bathing waters here.

What is CCW calling for?

With extreme weather becoming more common due to climate change, the rules that companies follow around the use of Storm Overflows must be updated to reflect this. Water and wastewater companies need to address Storm Overflows that harm the environment and invest appropriately in their sewerage systems to ensure they are fit for purpose. That must be part of a wider package of investment to also end the misery caused to families who are victims of having their homes flooded by sewage.

Given the significant potential impact on water bills, it’s imperative that customers have a meaningful say on these important investment decisions and have access to updates about how their money is being spent to prevent the need for Storm Overflows. It is essential that we protect the 1.5million customers who are already struggling to pay.

One of the ways we are seeking these changes is as part of the Storm Overflows Taskforce, led by DEFRA, which has been set up to eliminate the harm caused by Storm Overflows. We are also working in Wales with a Taskforce established by Natural Resources Wales, Welsh Government, Ofwat, Dwr Cymru and Hafren Dyfrdwy to evaluate and set recommendations for the current approach to the management and regulation of Storm Overflows in Wales. These recommendations will ensure the role of storm overflows in Wales is understood, improved, and fit for the 21st Century.

What should I do if I’m concerned about a possible sewage discharge near me?

If you are concerned about a possible sewage spill in a local body of water, you should contact the Environment Agency to report an incident. If you are concerned about a possible sewer overflow affecting your home, business or community, you should contact your local water or wastewater company. As part of our End Sewer Flooding Misery campaign, we are calling for improved compensation and support for repeat victims of sewer flooding.

What can I do to help?

We can all help to protect our local rivers, streams, lakes and beaches, as well as our communities, by taking care about what we flush down the toilet and rinse down our drains. Sewer blockages increase the pressure on sewerage systems. You can find here our tips for preventing blocked drains and sewers.