It is a remarkable building, which played a vital role in keeping Norwich's water free from sewage and cholera during the Victorian era.
But the imposing brick-built Trowse Pumping Station is now disappearing behind overgrown foliage, with concerns mounting for its future.
Civic watchdog, the Norwich Society, has warned that the building - which can be glimpsed by rail passengers heading in and out of the city - and others in the same complex are in danger of neglect.
The society has made calls for the pumping station's owner - Andre Serruys - to come up with firm plans for its future.
The building opened in the late 1860s after a campaign from people worried about the high level of pollution in surrounding rivers.
It contained three huge beam engines which lifted the city’s sewage from a sump under the building up to a sewage farm at Whitlingham.
A second pumping station was constructed at the site in 1909 and both buildings were listed at Grade II by Historic England in 2021.
But conservation charity the Victorian Society last year named the site among its top 10 most endangered buildings in the UK.
The society's president, comedy star Griff Rhys Jones, said the buildings were an indelible part of its social history.
The Norwich Society, set up to protect the city's heritage, agrees and has called for action to safeguard them.
In a statement, the society said: "In its centenary year, the Norwich Society is calling for vital action to save Trowse Pumping Station.
"We urge the owner to take immediate steps to protect both engine houses from further degradation, to put forward proposals for their re-use, and to agree for this unique site to be included in the East Norwich Masterplan."
Mr Serruys, who has plans for more than 600 homes at the May Gurney and Deal Ground site, said he had no control over whether the pumping stations were included in the East Norwich Masterplan - a blueprint for development in the area.
But Mr Serruys agreed the pumping stations were "remarkable" buildings.
He said he would welcome "any constructive input from the Norwich Society" were they to contact him directly.
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