Abstract: A water purifier (10) comprising an inlet conduit (12) with a high-pressure pump (18), a purifying unit (22) of the type including a filter or a membrane, an outlet conduit (28) for purified water, a sensor provided in said outlet conduit (28) for the control of the high-pressure pump (18), a tap point (38) at which the outlet conduit (28) opens, a non-return valve (32) provided in the outlet conduit (28), and a reject conduit (42) for concentrated, unpurified water. In the outlet conduit (28) for purified water, between the non-return valve (32) and the tap point (38), there is provided a pressure equalizing valve (34). The object of said pressure equalizing valve (34) is to compensate for the pressure drop that can occur in the conduit (28) for purified water in case of minor leakage.