A pub landlord has applied for a licence to sell water from what is believed to be Britain's oldest mikveh site.
Martin Hughes and his business partners have asked the Environment Agency for a licence to extract 15 million litres of water a year from Jacob's Well in Hotwells, near Bristol.
Mr Hughes bought the Hope and Anchor pub opposite the well 15 years ago without realising its historical significance.
"Like most people in Bristol, I was aware of an ancient well but didn't know much about it," he said. "Living so close to it, I started to find out more."
The Jewish community in Bristol dates back to 1188 and it is believed the mikveh was established around that time.
It was a fire station in the 1800s and in the 1970s was used by a water bottling production company.
"It was sold in Bristol blue glass bottles, which were very expensive to produce - and bottled water wasn't as popular then," Mr Hughes explained.
The well was rediscovered in 1987 when the Temple Local History Group was given permission to investigate the site and removed a wall, revealing a springhead with a chamber and two stone steps.
A Hebrew inscription, believed to read "flowing", was discovered on the stone lintel over the entrance, suggesting it had been a medieval mikveh.
But the origins of the site have come into question with archaeological experts Joe Hillaby and Richard Sermon suggesting it may have been a beit taharah - where the dead are washed before burial - given its close proximity to Bristol's medieval Jewish cemetery.
Local plumber Stephen Cook bought the site three years ago and used the front part as an office while capping the well in the rear of the building.
He was approached by Mr Hughes and Steven Kavanagh, who outlined its historical significance, and the three set up CHK Holdings to apply for a full licence to take water from the well all year round. "We explained he was sitting on something more valuable and interesting and we started to investigate more," Mr Hughes said.
"We're surprised that the city of Bristol is largely unaware of what's behind those doors and we'd like to make it publicly available. We're looking for advice from the Jewish community as we think there would be a lot of interest there."
Robert Jones, secretary of the Bristol and Gloucestershire Archaeological Society, expressed reservations about using the site.
"I remain concerned that the monument is vulnerable to unauthorised works, being currently behind locked doors and out of sight," he said.
"The monument is legally protected as a Scheduled Ancient Monument and it is a criminal offence to harm the monument in any way without consent."
Mr Hughes said the desire was to "protect it as a historical monument".