Coombe Conduit House

Coombe Conduit House is a conduit house built in 1538-40 with additions from the 17th and 18th centuries, located on Coombe Lane West in Kingston upon Thames. It was constructed as part of a water supply system for Hampton Court Palace, drawing from springs at Coombe approximately 5 kilometres to the north-east.

The building comprises two separate structures: an upper chamber and a lower chamber, connected by an underground tunnel approximately 25 metres long. These chambers were designed to collect, filter, and distribute water to the Palace under gravity through underground lead pipes.

The lower chamber is a rectangular single-storey building set four steps below ground level. It is constructed of 16th-century red brick with stone quoins and has a crow-stepped gable-ended roof on a brick plinth with stone dressings. The west-facing front elevation is built of squared random rubble below window-head level. The entrance features a tiled porch containing an arched doorway, above which is a two-light mullioned window. The side walls contain inserted round-headed windows, and the rear east elevation has a large sloping brick buttress. The interior contains arched recesses, an oval lead-lined cistern in the floor, and a smaller square cistern beneath a flagstone to the south.

The upper chamber, situated to the east of the lower chamber, is now ruinous with brick courses surviving to window level. It originally contained three separate compartments with lead water tanks flush with the floor. The central room has recesses on three sides and provides access to the underground passage at its west end. In the floor is an oval cistern with a stone cill. The northern and southern compartments were added during the 17th and 18th centuries as the surrounding water-table fell.

The connecting passage between the chambers has a four-centred brick vault. Water flowed into the upper chamber tank where sediment was allowed to settle, then passed through a pipe towards the top of the tank into the lower chamber, where it was filtered through a further tank before flowing out in a lead pipe to Hampton Court.

The conduit house was constructed following the acquisition of Hampton Court by King Henry VIII and the suppression of Merton Priory in 1538. An existing conduit at Hampton village, established by either Sir Giles Daubeney or Thomas Wolsey, proved insufficient. A summary account covering 1538 to 1545 records charges for "the condyte from Combhill" and a sum of £100 spent on construction. Three conduit houses supplied water from the Coombe springs: Coombe Conduit, Gallows Conduit, and Ivy Conduit. The water flowed under gravity through underground pipes, crossing the Hogsmill and Thames rivers via four tamkin houses—small brick buildings with stopcocks and expansion tanks used for leak isolation and repair. One such building, Gallows Tamkin, survives.

Records document repair work in the early 17th and early 18th centuries. In 1742, the Office of Works ordered a survey and undertook a major overhaul to increase efficiency. The conduit continued to supply Hampton Court until 1876. The upper chamber was damaged by bombing during the Second World War and sustained further major damage in 1943 when two trees fell upon it during a storm.