Rainwater Harvesting for Drylands and Beyond by Brad Lancaster

April 10, 2018

Finally, an Easy-to-Permit Three-Way Valve for Greywater-Harvesting Systems

by Brad Lancaster © 2018

Greywater harvesting—the practice of directing the drain water from household sink, bathtub, shower, and clothes washers to your landscape plantings—can lead to big water savings. It turns “waste” water into a free, on-site “resource” water. It also enables you to mimic the planet’s hydrologic cycle by using, or cycling, water again and again in a way that naturally improves its quality, making it available for many more uses and able to generate and sustain more life.

To ensure I capitalize on this I have a rule: I don’t plant a higher-water-use plant such as an exotic fruit tree until I’ve first planted (or harvested) both rainwater and greywater where I want that tree (see my book Rainwater Harvesting for Drylands and Beyond, Volume 2 for how I do this, or how to retrofit an existing system). That way free waters take care of my irrigation needs.

Thanks to the lead of Arizona’s greywater guidelines, many other states have similarly legalized the harvest of greywater as long as simple, common-sense guidelines are followed. Oftentimes, this includes the use of three-way diverter valves or a multi-drain system (see the greywater-harvesting chapter of Rainwater Harvesting for Drylands and Beyond, Volume 2, for more) that enables you to direct your greywater either to the landscape or the sewer/septic, based on what you send down the drain or how saturated or frozen your soils are.

The City of Tucson even requires that all new homes be built with greywater-harvesting stub outs.

But one hang-up, until now, has been finding a three-way diverter valve rated and approved specifically for use for drain water / greywater. Many have used three-way valves, such as the Jandy valve, made and approved for other uses with success. But sometimes the use of those valves has been denied for permitted systems due to their lack of being UPC-listed and IAPMO-tested and -approved.

Thankfully, the new FLO2 diverter valves are UPC-listed and IAPMO-tested and -approved for use in drain, waste, and vent-pipe applications. Thus they are approved for permitted greywater-harvesting systems.

The FLO2 valve — UPC-listed and IAPMO-tested and -approved for use in drain, waste, and vent-pipe applications. Thus legal for permitted greywater-harvesting systems.

Another nice advantage of the FLO2 valve is it has a 90-degree adapter, which enables you to extend its handle to whatever length you need. Thus the valve could be hooked up to your bathtub drain beneath the floor in your bathroom, yet the handle could be conveniently accessible within the bathroom.

FLO2 valve with 90-degree adapter attached

See here for more images comparing the FLO2 valve to the Jandy valve.

See here for examples of, and reasons why I love, convenient three-way valve installations.

See here and my books below for more greywater- and other water-harvesting resources and options.

Happy Harvesting!

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