GreenTown Los Altos

Getting Your Gray Water Mojo


Aug 2015


Gray Water. You’ve heard the term, but what is it and why should you care about it?

Now that your lawn is no longer a water burden, if you’re looking to save even more water then gray water is one option to easily “reuse” water.

Gray water systems use the water from your washing machine’s laundry cycle to irrigate your outdoor plants. Gray water from your washing machine is relatively clean, while black water is waste water, such as from toilets, that cannot be reused until it is cleaned and sanitized through the sewer system.

If you missed this Gray Water Workshop, contact us to find out how you can join us next time!

Professional installer Alan Hackler, owner of local sustainable landscaping company Bay Maples, recently led a hands-on Laundry-to-Landscape Gray Water Workshop at a Los Altos home. Those attending learned about and contributed to the step-by-step process of attaching and installing the piping to use the gray water directly from a washing machine to water trees in the landscape.

Hackler’s company uses Blu-Lock piping with its high-density polyethylene and pressure fittings and a switch to direct the gray water route between sewer and landscape. Water used to wash dirty diapers, greasy materials, or otherwise soiled loads unfit for landscaping use is considered black water and must be transferred to the sewer so segmenting the water is the key to success.

Why reuse water from washing machines?

Washing machines are good sources of gray water because they already have a pump and are usually located near the exterior of the house, providing easier access than other sources of reusable water in the home. Washing machine water is considered gray water (not black water) because it is clean enough to reuse in landscaping.

How muchDSCN2994 water does the laundry-to-landscape option allow me to use in my garden?

Per laundry cycle, laundry to landscape would give you 10 to 15 gallons of landscaping water from new washer models and 25 to 30 gallons from older models.

Are there tips for using washing machine gray water in my garden?

The laundry-to-landscape method has some dos and don’ts. This method cannot be used with a drip system or with lawns because the gray water comes from underground, is filtered through mulch and plants, cannot be sprayed, and must be released without runoff. Mulch or other material must cover the release point, which can have a flooding effect from the laundry-to-landscape piping.

Landscapes that benefit from the water from washing machines are water-loving riparian native plants that can survive the flooding effect, but you can attach a hose to water other plants and trees, such as ornamental plants and fruit trees.

Does it matter where my washing machine is located in my home?

The water from a washing machine needs to be pumped into the landscape, and the farthest distance a washing machine can pump water is 50 level feet, measured from the bottom of the washer. The preferred location of a washing machine is by an exterior house wall to enable easy transfer to the landscape. Pipes can be positioned through a home’s crawl space if the washer is not near an exterior wall, but piping over concrete patios is difficult.

For washing my clothes in a laundry-to-landscape system, must I be mindful of the soap and laundry additives I use?

The best laundry soap DSCN2999to use with a laundry-to-landscape system is one that is biocompatible, which is distinct from biodegradable soap in that biocompatible soap breaks down and benefits the soil while biodegradable soap breaks down but does not benefit the soil. Popular biocompatible brands are ECOS, Oasis, and Dr. Bronner’s.

For your garden to thrive, your detergent should not contain boron, bleach, sulfides, phosphates, and salt. Powdered laundry detergents are salt-based so should be avoided.

By Malar Ganapathiappan

One Response to “Getting Your Gray Water Mojo”

  1. Mike Castle

    Thanks for this post! This is super helpful.

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