Beavers would help clean water around the reservoir says South West Water
Concerns have been raised over plans to release beavers into the wild, close to a reservoir on the boundary of Devon and Cornwall.
South West Water is considering a trial to see if they can help improve water quality around Roadford reservoir.
Beavers are to be introduced in trials in Scotland in May.
But there are concerns over possible damage to trees after a beaver recently escaped in Devon and left a trail of fallen trees 20 miles away in Cornwall.
Councillor Mark Butler, of Broadwoodwidger Council, told BBC News: "When you see the damage done by a single beaver, it makes those fears grow."
The escaped animal is believed to be felling trees up to 20 miles (32km) away, on the banks of the River Tamar near Gunnislake, Cornwall, from where it escaped in Lifton, Devon.
The beaver is still at large, but its owner, wildlife consultant Derek Gow said introducing beavers would be a "good idea".
Beaver-felled trees have been found 20 miles away from the farm
He said: "Their dams trap silt and act as a natural filter.
"And they work 24 hours a day, so it is a sustainable source of clean water."
He said tree canopies in the area could be reduced, but any fallen trees would encourage new saplings to grow.
"It creates a much better wildlife environment when you have beavers around."
Martin Ross of South West Water said: "If we don't do this we face more investment in concrete and chemicals as well as energy to provide clean water over the next 30 to 50 years."
Beavers were hunted to extinction in England and Wales during the 12th Century and disappeared from the rest of the country 400 years later.
They were hunted for their fur and throat glands, which were believed to have medicinal properties.