The Greywater Bootlegger
A man who will remain anonymous, in an undisclosed California city has set up his washing machine on his back porch. He mixes in a special detergent from a green container and hits the start button. After each load of soiled pantaloons and plaids, dirty water flows into a nearby garbage bin on wheels. Shielded behind his tall privacy fence, he wheels the bin over to the edge of the porch. He dumps it in his yard. The water gushes into a trench he's dug and begins soaking into the ground, watering mints, edible canna, and a grape vine. Folks, call the police, call the building inspectors — what we have here is greywater bootlegging in progress.
That's right. Our seemingly good, water-minded man is breaking the law. Greywater itself is a perfectly legal substance — it's basically any water that runs down sink, shower, tub, or laundry drains. Greywater, if used properly, presents little risk to human health and is an obvious choice for irrigating home landscapes. Greywater is opposed to blackwater — water from toilets (and some say kitchen sinks) which may contain substantial organic matter and/or pathogens.
Until recently, most state laws restricted the diversion of greywater from its path to the sewer treatment plant. California law changed, thanks to an avid and informed group fighting to "legalize sustainability." Now permitted greywater systems can be used to irrigate landscaping. But, as our bootlegger probably doesn't realize, there are still rules about how.
Sustainability Legalized
To keep us in the clear, local nonprofit SLO Green Build has worked with several other nonprofits and government agencies to create the Greywater Manual, specifically tailored to our humble county. While there might not be any real danger of dumping laundry water on our plants, the manual quickly makes it apparent that this is surface discharge, and is not allowed. In reality, our bootlegger could probably save himself some time and trouble — and avoid run-ins with the law — simply by hooking his washing machine into an allowable greywater system which discharges water below the surface. To be completely legal, he would also have to apply for a permit from appropriate authorities.
Until recently plumbing codes treated greywater fearfully, confusing it with blackwater. Coming out of a human history rampant with plagues and disease, we are right to treat our waste cautiously. But some argue that greywater poses little or no threat. Brad Lancaster, a pioneer in water capture and reuse, lays out cogent arguments at his company's website Oasis Design about why greywater doesn't really need to be discharged underground, or even necessarily permitted. Yet the law is the law, for now.
Water = Energy
Overall, greywater from sinks, showers, and washing machines could take care of most, if not all, of our outdoor watering needs. Besides conserving water, it happens that saving water also saves energy. Known to water and energy geeks everywhere as the water-energy nexus, water requires energy for treatment, pumping, use (such as in-home heating), and finally disposal. In California, according to the California Energy Commission, up to 20% of the state's electricity use is attributed to moving, using, or getting rid of water. Using greywater to irrigate landscaping cuts back on both upstream (think pumping and water treatment) and downstream (think wastewater treatment) energy use. Most of the energy use related to water comes from heating it, likely for showers, washing machines, etc. However, a substantial 4% of California's electricity goes towards drinking water treatment, pumping, and wastewater treatment — energy use that could be easily avoided.
Create Your Oasis
Start simply, tap into one or two sources of greywater in your home. Focus on sources that will take minimal plumbing to route outdoors. The SLO Green Build Manual ranks various systems by material cost, complexity, and sustainability. Many washing machines are located near an exterior wall, and may be easily diverted.
To use greywater on your plants, you'll have to be careful about what you put down the drain. Avoid laundry detergents that contain carbonates, sulfates, chlorides, and boron, which can build up in the soil and kill plants. Many alternatives are available (pg. 27 of the SLO Green Build Greywater Manual suggests some). Some plants are more tolerant of greywater than others. Drought tolerant and/or native plants that handle it well include oaks, coffeeberry, redbud, penstemmon, lavender, yarrow, sage (but be careful not to overwater — some don't like summer water at all!). Greywater can also irrigate food producing plants, though it is advisable to avoid direct contact between the water and the edible part of the plant. Some options include plum, apricot, peach, apple, pomegranate, grape, and fig. One Cool Earth has these and other plants available from it's Paso Robles GreenWorks Nursery.
Swales Tales
Okay, so you're flaunting your rainwater catchment system and growing crazy with greywater but you want to do more to save water? Check out next month's installment, we'll hit the trenches to end water wars. Literally, we'll hit the trenches, but we'll call them swales. We'll learn about the the self-tilling, composting, water-capturing machine that is German hugelkulture. And we'll learn how to work with gravity in capturing runoff!
Resources
Oasis Design
SLO GreenBuild Greywater Manual
California Energy Commission Water-Energy Nexus
Swallowtail butterfly on milkweed. (Photo: Shelley Ellis)
