Eastside Harvest House Week 27: Growing Up Green

In order to deliver the house to the owners with completely full rain tanks, we needed to start filling them two months in advance. In late February the plumber connected the various pipes and fittings to make them into a working system.

Upstream of the tanks is a vortex filter that siphons off leaf debris. The four tanks are connected near the bottom so the water in them rises and falls in unison. The master tank has a pipe at the top where rain flows in by gravity and a hose floating inside through which water is sucked out by the pump.

The pump cycles on and off to pressurize a blue bladder tank which can handle surges, like the clothes washer turning on. From there the rain is either sent unfiltered to the irrigation system or filtered to the plumbing fixtures in the house. The filters get down to 1 micron, smaller than bacteria, and then any remaining viruses are sterilized with UV light. The final step is a carbon filter to improve taste.

In among the filters are shut off valves for servicing along with gauges and meters for diagnostics. The meters are connected to the home’s digital monitoring system so the homeowners can track their water usage online.

Expected maintenance involves annually replacing the UV light and quarterly replacing the two filters. If the tanks need to be cleaned out for some reason, we can open a valve and let them gravity drain into the rain garden outside.

George Ostrow is principal of VELOCIPEDE architects and member of Northwest EcoBuilding Guild, U.S. Green Building Council, Passivehouse Northwest and Built Green.