The Balmain Reservoir is a 2,376,000-imperial-gallon (10.80 ML) disused, covered reservoir located under Gladstone Park in Balmain, in the Inner West of Sydney, New South Wales, Australia.

Balmain is a suburb in the Inner West of Sydney, New South Wales, Australia. Balmain is located two kilometres west of the Sydney central business district, in the local government area of the Inner West Council.