Modular Rainwater Cistern
This rainwater harvesting system stores water in a 4,000 gallon modular underground cistern during and following a rain event. Water is pumped out via a submersible on-demand pump located in a pump shaft adjacent to the tank; then through a filter bank; then out to subsurface dripline irrigation. An automated source selector will irrigate with rainwater when there’s water in the cistern, and switch to municipal water when the cistern is empty.
Beginning Excavation
Excavation Finished, beginning to assemble cells in garage
Installing fabric liner to protect impermeable vinyl liner
Installing impermeable liner and starting to install rainwater cells
Continuing installation of cells.
Installing pump shaft. Modular cells are completely wrapped in impermeable liner like a birthday present, to create an underground tank.
Site drainage – gravity-flow to in-ground prefilter (Graf MiniMax). Filtered rainwater flows by gravity into cistern. If cistern is full filter will overflow to street by gravity.
Pump shaft (w/ blue tape) with pump-out line to filter bank behind garage. All pressurized rainwater pipes are labelled.
Float switches in tank to control irrigation source – when tank is empty irrigation switches to municipal water.
Two-stage filter for sediment only, so water will be compatible with subsurface dripline.