A dampening valve unit (40), for use in a liquid distribution system. A feeding conduit is evacuated of liquid after an associated tap unit is closed and refilled with liquid after the tap unit is opened. The unit (40) comprises a dampening chamber (26), connectable to said feeding conduit, and a liquid stop valve unit (1'), connectable at an inlet end (22) thereof, to said associated feeding conduit and which has an outlet end (24) being connectable to said associated liquid tap unit. Said dampening chamber is adapted to collect gas and is connectable to said associated feeding conduit via a passage (23). The passage is directly connected, without any restrictions therebetween, also to a liquid stop valve (2, 18) at said inlet end. The passage is always open at the dampening chamber for fluid connection between the passage (23) and the dampening chamber (26).