According to the Regional Association of Friends of Water Mills (ARAM), fishing federations are demanding their removal because they argue that they are hampering the recovery of migratory fish.
Serge Caprais, president of the association in Lower Normandy, said that they must be preserved as they are an important part of the regionâ€™s heritage.
â€˜After castles and churches water mills are the most numerous type of heritage building. There used to be thousands of mills in Manche, for example, but today their numbers are falling,â€™ he explained.
He pointed out that there are over 100 inhabited mills and the oldest of them dates back to the sixteenth century. He added that they also have an ecological role to play in conserving the environment and could be used for producing green energy. Also owners of mills like to keep their water wheels working if they can. There are also restaurants with working wheels.
Mr Caprais does not believe that the water wheels are behind the drop in migratory fish numbers in the rivers of Normandy. He put the blame at the door of pollution.
But the mills are also under threat from the increase in interest in river sports such as canoeing and from a European Directive which provides for rivers to be restored to a good ecological state by 2015. There is concern that working mills could be degrading the quality of the water.
Owners are also coming under pressure from the Seine-Normandy Water Agency which has been seeking to have poorly maintained mills and wheels demolished because of their affect on the water quality.
But the association is concerned that removing poorly maintained mills or their wheels could have a serious environmental impact. Mr Caprais said that it can affect the dame that supplies the mill, water retention in the surrounding area and ultimately the foundations of buildings.
An example of proud water mills owners is Noel and Monique Jeanne from Bernieres-le-Patry in Calvados. They use their two wheels to generate electricity in winter and they also have a small paddle used to mill flour. The couple also make bread and cakes in their bread oven.