Cisterns involve the collection of water typically via the roof. The idea of a cistern is very similar to using a holding tank, lake or river. Water quality may sometimes be a concern with cisterns but with proper filtering and treatment they make a viable option for many locations. A system of gutters and downspouts directs the rainwater collected by the roof to the storage cistern. The cistern, typically located underground, may be constructed of various materials including cinderblock, reinforced concrete, polyvinyl or precast concrete, fibreglass, or steel. The cistern supplies water to the household through a standard pressurized plumbing system.