The Rivers Trust has compiled the map of areas most at risk of pollution as part of its Together for Rivers campaign which urges the government to introduce designated bathing waters in well-used rivers.
It comes as MPs have been accused of voting to allow water companies to dump raw sewage in rivers. A proposal from the Lords to the Environment Bill that would have placed legal duties on the companies to reduce discharges was defeated by 265 MPs' votes to 202 last week.
Water companies discharged raw sewage into rivers in England more than 400,000 times last year, according to figures published by the Environment Agency.
Environmental campaigners have condemned the move citing risks of pollution to surfers and swimmers in hard hit areas.
The group Surfers Against Sewage highlighted 20 beaches along the Sussex and Hampshire coast line that already have a pollution risk warning in place.
The brown circles on the map show the locations where the most sewage overflow can be found. According to the map north west of England including Manchester and Liverpool are among the areas most impacted by sewage overflow. A storm sewer in Manchester overflowed 114 times for a total of 403 hours in 2020, according to the map which uses data from respective government environment agencies across the UK and Ireland.
Untreated sewage, including human waste, wet wipes and condoms, was released into waterways for more than three million hours in 2020.
The Environment Agency allows water utilities to release sewage into rivers and streams after extreme weather events such as prolonged heavy rain to protect properties from flooding and prevent sewage backing up into streets and homes.
The agency says that overflows are “not a sign that the system is faulty”, and that they are “a necessary part of the existing sewerage system”.