The reservoir was built in 1879 on the site of an earlier reservoir built by the Llandudno Water & Gas Company in 1857. It has a capacity of 956,000 gallons.
From what I can work out the original reservoir was fed from the open St Tudno's reservoir (below the church) and later from the pumping station in Water Street, but, from 1879 the new reservoir it was fed from the Dulyn supply. Water from Dulyn could reach a now demolished pumping station - which stood just above Black Gate - by gravity so the Fach Reservoir gradually became less important - particularly as many properties in the town now had storage in their attics and its draw-off water level was about the same as most properties' higher floors. In World War 2 it was kept full of water as a reserve in case of fire caused by enemy action and was used as a standby until the late 1960s. The structure was transferred from Welsh Water to Conwy CBC some years ago.
I am not sure what people mean by the other door. There is a small building with a door between the Fach Reservoir and the site of the amphitheatre. This was a small reservoir or tank but it was supplied from St Tudno reservoir and was used exclusively by Llandudno UDC gardens department. If anyone is familiar with the tank at the junction of Bryn Pydew Road and lane down to Ffolt they may see a similarity in design.
