No.1 Reservoir

No. 1 Reservoir is an underground reservoir built in 1824 for the Cheltenham Water Works Company, designed by civil engineer James Walker. It has a capacity of 413,000 gallons.

The reservoir is constructed from limestone, with a brick roof. The entrance portal is made of rubble stone with limestone ashlar dressings and features wrought-iron railings. The portal, located above ground on higher ground at the rear, is approximately 2.5 meters high. It includes an entrance bay with a square top, a central doorway with a flat limestone lintel, and limestone ashlar quoins. Curving ashlar walls flank the portal, sweeping downwards and forward to meet the ground, topped with spear-headed railings that extend to either side.

The underground reservoir itself measures 25.6 meters square and has an internal height of 4.3 meters. It consists of four parallel rectangular chambers with walls made of limestone masonry, inverted-arched masonry floors, and brick jack-arched roofs. Each internal wall features four arched openings that allow water to flow between the chambers.