Boater error caused the Grand Union Canal at Berkhamsted to overflow.
Waterways maintenance teams rushed to the canal that runs behind the town centre Waitrose on Monday afternoon after reports that water was flooding the surrounding area.
At first it was feared that the flooding was the result of vandalism.
But it was discovered that a boater had accidentally failed to close the lock paddles securely, which meant water was allowed to flow into a section of the canal and then overflow.
Spokesman for the Canal and River Trust Joe Coggins said: “We had teams go down there and they readjusted the water levels.”
The trust is looking for volunteers to become summer lock keepers on a stretch of the canal at Marsworth.
If you’d like to know more, visit www.canalrivertrust.org.uk/volunteer