Abstract: Contact surfaces of a water meter (1) and a base (2) of a meter support (3) comprising a water inlet duct (4) and a water outlet duct (5) are each bordered by an annular shoulder (6, 7). An assembly ring (8) is provided so as to keep the two annular shoulders (6, 7) in contact, this ring (8) comprising slits (9) separating a series of elastic fingers (10). The ring (8) comprises moreover on its inner face an annular groove (11) complementing the two annular shoulders (6, 7). A rigid collar (15) force-fitted onto the elastic fingers (10) and bearing against outwardly projecting lugs (12) at the ends thereof keeps the annular groove (11) against the annular shoulders (6, 7) which are in contact.