Not Your Daddy’s Rain Barrel: A New Rain Tank Design Specification

Rainwater harvesting tanks
Rainwater harvesting tanks are available in a wide array of sizes to fit individual needs.

Archaeologists tell us that rain tanks and cisterns have been around since the bronze age. They are still a major part of urban infrastructure in Europe, Australia, New Zealand, India and the Caribbean. But try finding them in the Bay watershed, or in any state stormwater design manual. Despite their prime advantage of using stormwater as a resource rather than something to be disposed of, they are currently not much of a weapon in our Bay stormwater arsenal.

Part of the reason has been the lack of a design specification for rain tanks. CSN, in partnership with several rainwater harvesting experts, has filled this gap, by releasing a rain tank specification. This new specification is different in that it seeks to optimize the total amount of runoff reduction from the roof, through internal water use, outdoor irrigation and detention/release of rainwater into secondary runoff reduction practices. A slideshow, developed by CSN, provides more visuals on the new rain tank concept.

Construction of underground rain tank[/caption]