Taps with check valve

Check valve

— a valve built into the tap that does not allow water to move in the opposite direction — from the tap to the water supply. Such a situation can arise, for example, when there is a large difference in pressure between hot and cold water — when hot water "displaces" cold water back, or vice versa. In addition, check valves are necessary for the correct operation of water metres; such valves can be installed as separate devices, but sometimes it is more convenient to purchase them as part of the tap.