The beavers build dams which filter water
A water company has sent a member of staff on a trip to Germany to study beavers, ahead of plans to re-introduce them to Devon and Cornwall.
South West Water, which has the highest charges in Britain, wants to install the rodents at Roadford reservoir near Launceston and Okehampton.
It hopes the dams the animals build will save money on water treatment.
The company said 20 local people went on the fact-finding trip to Bavaria, but it only paid for one employee.
The visit was organised by wildlife consultant Derek Gow.
South West Water said it paid only a "minimal amount" to send its environmental manager on the five-day visit, but could not reveal what that figure was.
A spokeswoman said: "Beavers clean and filter water which could offer a more sustainable solution to protecting the drinking water supply from blue-green algae than costly upgrades to our water treatment works.
"The trip has been organised... so that people who live near Roadford Lake... can find out how beavers live in the natural environment and gain an informed opinion about the project."
Some local residents are worried that the animals will destroy trees and plants and criticised the Bavaria trip.
Keith Woodward, chairman of Broadwoodwidger Parish Council, said: "We're a bit concerned at the way the whole thing's been handled in a rush.
"People who own land which abuts the reservoir were not all invited on the trip.
"We're concerned that their voice is heard on this."
Mr Woodward confirmed that district and parish councillor Marion Perkin and another parish councillor had also gone on the German visit.
A beaver, being raised by Mr Gow for release in Scotland, recently escaped from a farm in Devon and left a trail of fallen trees 20 miles away in Cornwall.
Beavers were hunted to extinction in England and Wales during the 12th Century and disappeared from the rest of the UK 400 years later.