Extinction Rebellion protesters have taken part in demonstrations against "disgusting" river pollution.
The campaign accuses companies including Wessex Water of failing to protect England’s waterways from sewage and chemicals.
Activists used bridges on the River Avon to promote their campaign on 12 December.
A Wessex Water spokesperson said a "substantial amount of money" would be needed to alleviate the problem.
In a report by the Environment Agency (EA), it said England’s rivers were polluted with chemical sewage discharge, farming pollutants, and industrial chemicals.
The EA also the Envrionment Agency (EA) said Somerset's rivers had unacceptable levels of mercury compounds and other harmful chemicals.
Extinction Rebellion, also known as XR, organised simultaneous protests throughout the South West in response to this.
XR Bath representative Stephanie Laslett said: "Wessex Water, which is one of the better performing water companies, released raw sewage on 13,876 occasions over 107,404 hours in 2019."
A Wessex Water spokesman said their storm overflow systems release "predominantly" rainwater with a dilute amount of sewage during heavy rainfall to protect homes and businesses from flooding and sewage backing up into streets and homes.
He said: “In an ideal world we wouldn’t have storm overflows, and we support ambitions to reduce the number of times they operate.
"To upgrade the system is simply not feasible without demolishing buildings, causing serious disruption and investing substantial sums of money."
Johnny Palmer, owner of the Warleigh Weir, a popular wild swimming spot near Bath, said it is "great" XR is adding to the conversation on river pollution.
"I get daily updates from Wessex Water as to when their sewage flows into the rivers and in the last two days, it’s happened three times upstream from the Warleigh Weir.
"It’s disgusting in a first-world country."
Bradford-on-Avon resident Nicky Reynolds, also an XR member, said: “The Avon is polluted with sewage. It's not safe for wildlife and it's not safe for us.
“There are fishermen, kayakers and walkers all along here and it has become hugely popular with wild swimmers but many don’t realise that raw sewage is frequently discharged straight into it.”