Pump House in Withy Wood

Pump house serving Westonbirt House, built in the 1860s (possibly up to twenty years earlier) with later additions and alterations. The building was constructed to overcome the shortage of reliable water supply in the vicinity of Westonbirt House as part of a combined water extraction scheme involving hydraulic rams and a water pumping mill.

The pump house is built largely underground from Cotswold stone with a brick annex. A flight of steps on the west side provides access down to the machinery chamber. The hipped roof is supported by two machine-cut trusses with raking struts and is partly covered by Cotswold stone slabs.

The main room contains a pitch-back cast iron water wheel with a single set of arms, fed by a penstock pipe with overflow valve supplied by a leat from a pond impounded behind a dam. The rotary power from the wheel was transferred via vertical geared cog wheels to a horizontal crank shaft. Three crankpins linked to piston rods provided the plunging motion to drive a triple-valve cast iron pump. The machinery is supported on two parallel brick-built bases. The pump bears the name of its manufacturers, Easton and Anderson of London, dating from the 1890s. Water was pumped approximately six kilometres to the house.

A brick-built underground annex chamber leading south from the access steps contains remnants of iron pipe work associated with a disused hydraulic ram. The waterwheel-driven pumping machinery was updated in the late 19th century. The hydraulic rams no longer survive.

According to an unpublished 1912 account by F. Godwin of the Westonbirt waterworks, hydraulic rams on each side of the valley were fed by separate and independent springs, with a dam at the bottom of the rivulet forming a head of about ten feet below which the small waterwheel was fixed. The waste from the rams contributed to turning the waterwheel.