The piezometric height of the water distributed by the indoor networks mentioned in 3° of article R. 1321-43 must, for each network and at any point where it is made available, be at least equal to three metres at peak consumption time.
When the networks serve buildings with more than six storeys, pressure boosters and pressure tanks complying with the provisions of article R. 1321-55 may be used.
The provisions of this article do not apply to distribution systems existing before 7 April 1995.