Before buying an «  étang » you have to be aware of the environnemental laws applicable to your étang. And remember that in French « étang » and « lac » do not refer to the same thing : an « étang » has usually been created by men whereas a « lac » is natural.

The law is different according to the type of « étang » bought.

There are 4 types of étang :

- « étang fondé en titre » ie which have a deed and including those created before April 15, 1829 ( mentionned on the Cassini map or atlas Dieu préfet)

- « enclos piscicoles or piscicultures à valorisation touristique » where there is fish for touristic purpose ie authorised by  an « arrêté prefectoral » valid for 30 years 

- « eaux closes » ie closed water which means no permanent communication with a river, the fish cannot go to or from the étang to a river( small or big)

- « eau libre » free water , permanent communication between river and étang

It is not useless to make a survey for an etang before the sale. The laws are very strict.