The group of anonymous residents – dubbed the ‘Berkshire Banksys’ – are taking action over polluted water in Hampstead Norreys.
One sign warns drivers to keep their speed low to avoid splashes in the ‘Poo-nami’ area – while another has changed Water Street to ‘Sewage Street’.
The signs have been praised as a typically British method of protest.
But the humour is intended to highlight instead of detract from the serious impacts of local sewage spills.
Locals complain they’re regularly splashed with sewage in the street by passing cars.
And Steve Masters, who lives on a narrowboat moored on the Kennet River in nearby Newbury, compared locals wading through sewage to Dickensian or Victorian standards of living.
The 54-year-old RAF veteran, who is also a local councillor for the Green Party and will be standing as the party’s parliamentary candidate in upcoming general elections, said: “The signs are there to draw attention to these problems.
“They reflect the collective mind of the residents. It’s frustration manifesting itself in a very creative and typically British defiance.
“I know many people have shed tears over this – it’s not a laughing matter.
“But when the chips are down, people do find some solace in humour.”
The signs in Hampstead Norreys include some placed along the River Pang, which runs through the village, reading: ‘More species less faeces.
‘This is one of only 210 chalk streams on Earth – a unique habitat for many species.
‘Keep pollution out.’
Another sign at the side of a road warns drivers to keep to ten miles an hour, saying: ‘This is not rainwater, it is sewage – no splash zone.’
Mr Masters, a councillor for Speenhamland on Newbury Town Council who now works in renewable energy sales, said the problem of sewage spills in the area was not new.
“A lot of Thames Water’s sewage is finding its way onto roads and into chalk streams,” the grandfather-of-three said.
“This is not something that has just happened – it has been going on for months and years but is now becoming more and more frequent and longer lasting.
“These are biodiverse, nationally and globally significant chalk streams and special habitats.
“Some people have had faeces, tampons and sanitary products on their road since before Christmas.
“It’s a public health hazard. Four members of one family in Hampstead Norreys have been in hospital with sickness as a cause of the sewage that has infiltrated their house.
“It’s an appalling state of affairs when children are walking to school through this.
“We are in the 21st Century, not Dickensian or Victorian Britain, yet people are having to walk through raw sewage in their homes and on their roads.
“At what stage does it become a public health crisis?”
Cllr Masters added that though Thames Water should take the brunt of the blame for the spills, regulatory authorities such as Ofwat and the Environment Agency need greater powers to encourage water companies to fix the problems.
He said: “Thames Water are very much a part of this problem but a lot of this is down to the government and a lack of regulations from the authorities charged with policing this.
“It’s easier and cheaper for the water companies to pay the fines than address the problems.
“We need to bring the water companies back into public ownership.
“Climate change will only lead to more extreme weather events and resulting flooding.
“Living on a boat on a river polluted with sewage makes it personal to me as well. Nobody wants to live in an open sewer.”
Earlier this month, a Thames Water spokesperson told the BBC: “We are working hard to make these discharges unnecessary and have published plans to upgrade over 250 of our sites, including our Hampstead Norreys sewage treatment works.
“This project will increase the treatment capacity of incoming sewage and reduce the need for overflows during wet weather.”
Thames Water was approached for further comment.
