Abstract: There is provided a fluid side of a high pressure water pump is to be used with a pump having a power side which has at least one piston and at least one stuffing box. The fluid side consists of a unitary substantially block shaped fluid end which defines a generally cylindrical fluid inlet bore, a generally cylindrical fluid outlet bore, and at least one generally cylindrical working bore. The working bore intersects the fluid inlet bore and the fluid outlet bore. Within each working bore there is sealably provided a substantially tubular suction/discharge seat which has a longitudinal axis, a suction end, a discharge end, an outside surface extending between the suction end and the discharge end, and an inside surface extending between the suction end and the discharge end. The suction/discharge seat defines a plurality of fluid holes at the suction end which provide a flow path of a fluid from the fluid inlet bore to the inlet end of the fluid end.