Abstract: A pump housing assembly which includes a pump casing (12) and a liner (20), the pump casing (12) including at least two parts (13, 14) which are adapted to be connected together in an assembled position wherein the pump casing (12) includes opposed front and rear sides, the two parts (13, 14) of the pump casing (12) when in the assembled position have a common junction region which is disposed within one or more planes which pass through the front and rear sides of the pump casing (12) when in the assembled position.