Our plan, published in early 2024, sets out when each of the 14,187 overflows in England will benefit from our unprecedented levels of proposed investment – we are ready to more than triple what we’re spending (up from £3.1bn – which includes Thames Tideway – to £10.2bn).  

We also recognise that transparency is an important part of how we will reassure people about the progress being made. That’s why we are also committing to the world’s first ever national data hub to provide data on the operation of all 15,000 sewage overflow sites across England. This will empower people will information and improve accountability.

The rules that determine the legality of a spill are set out in each overflow’s permit, with which compliance is very high (about 97% in 2022). We get though that this also misses the point because regardless of legality, people want these things gone.

The engineering solutions for the removal of CSOs are complicated as many of the older sewers serve towns and cities running under buildings and roads. The ‘replacement of all CSOs’ would take many years to achieve and result in major disruption. This is not a reason not to do it, but there is no quick fix.

The cost to re-plumb these areas is estimated to be up to £600 billion nationwide. This level of investment needs to be agreed by regulators and balanced with keeping customer bills affordable. Water companies have been addressing CSOs for years, taking a prioritised approach to those causing environmental harm first.  

If CSOs are removed, then solutions are required to address excess surface water which will cause flooding. Adequate flood defense systems must be installed which include solutions for the storage of rainwater from highways and buildings. This will require land acquisition which can be difficult in urban areas. 

The biggest impact to the environment when Storm Overflows operate is when non-flushable items cause blockages in sewers. These discharges are more harmful as they are not predominantly rainwater. Wet wipes, cotton buds, sanitary products and Fats Oils and Greases (FOGs) all create blockages in the pipes that make Storm Overflows discharges more likely.  

Reducing the likelihood of blockages caused by non-flushable items such as wipes, and FOGs is a key way that individuals can help. 

Companies have published their Drainage and Waste Water Management Plans (DWMPs) which have informed their investment for PR24.  

DWMPs are the plans for the future of drainage, wastewater and environmental quality and provide the basis for more collaborative and integrated long-term planning by organisations that have interests and/or responsibilities relating to drainage, flooding and protection of the environment. The production of DWMPs is led by water companies, all of these organisations have a part to play in their creation. By planning together, organisations are more likely to work together to deliver improvements that benefit the communities we live and work in. 

No, they are in many other European countries too. The UK actually has a much lower number of CSOs than other countries and in fact, some countries do not even know how many they have. England and Wales achieved 100% monitoring at the end of 2023.

Companies first published their plans for investing in sewage works and overflows in October 2023. Since then, they have been discussing the detail with regulators and the government. We have now published an updated and consolidated version summary of these plans with detailed of planned activity across England.