United Utilities has released details of how it will deliver cleaner rivers, beaches, and lakes across the North West – the biggest investment of its kind in the UK.

Schemes to help towards this goal have already been completed at sites in Nelson, Rossendale, and Chorley, while schemes are underway at other sites in Burnley and Eccleston.

The water company says by 2050 its goal is to ensure storm overflows, the relief points that prevent sewers from backing up and flooding homes and businesses in heavy rain, operate less than 10 times a year.

The Storm Overflow Reduction Plan, expected to cost some £19 billion in the North West region alone, will meet the new requirements of the Environment Act 2021, bringing a massive reduction in sewer pollution entering the region’s waterways.

A dashboard has been published showing the locations of every storm overflow in the UK, with a timescale for achieving the target of 10 operations a year.

The first phase of the plan will take place up to 2030 and will involve £3bn of improvements at 437 sites across the North West.

Some of the projects already completed include in Nelson, where a storm water storage tank the size of 25,000 bathtubs has been built and is reducing storm spills into the River Calder.

As well, Rossendale Water Treatment Works has been upgraded to provide greater storm water storage capacity, and in Chorley new storm storage tanks have been built to help improve 38km of the River Douglas.

Other schemes underway include at Burnley Wastewater Treatment Works, where a £77 million upgrade will enable the facility to meet growing demand from the town and surrounding towns by increasing capacity by 27 per cent.

The increase and the introduction of more stormwater storage will also reduce the number of times that storm overflows operate in periods of heavy rain.

Meanwhile, in Eccleston, a new wetland is being created which will filter and clean storm water before being returned to Syd Brook.

Jo Harrison, asset management director at United Utilities, said: “At United Utilities, our purpose is very clear – we don’t just supply water, we also want to make the North West greener, stronger and healthier.

“The multi-billion pound programme we are now embarking upon will see the biggest overhaul of the region’s sewer network in a century. 

"Not only is this now enshrined in law, it is what our customers expect and it’s the right thing to do.”

There are more than 2,200 storm overflows within the wastewater system across the region, which are designed to prevent flooding and provide a route for water to take when sewers fill during heavy rain.

Since December 2023, every one of these sites is now monitored, allowing United Utilities to build a picture of how often each site operates and which should be tackled first.

Improvement work will be prioritised at the sites which operate most frequently or which discharge into bathing waters or environmentally sensitive locations.

Ms Harrison added: “We are making a fundamental change to the way our sewer system has been designed and change on this scale cannot happen overnight.

"We are re-plumbing our drainage systems, building storage tanks to increase the capacity, separating rainwater out of sewers, and harnessing the power of nature to treat storm water before it is returned to the environment.

"Work has already started and people are going to see much more of this over the next 25 years.”