While California has seen near-normal amounts of rain and snow this past year, the previous four winters were exceptionally dry. As a result, nearly 90 percent of the state is still suffering drought conditions, according to the U.S. Drought Monitor.
“The reality of climate change is that hotter, drier weather will become the new normal in the West,” said Tracy Quinn, senior water policy analyst for the Natural Resources Defense Council. “It’s essential that California implement permanent regulations that build on the conservation we’ve achieved during this unprecedented drought and prepare our state for that new reality.”
Graywater use for landscape irrigation is a viable component of a permanent, sound water conservation program.
Water used for bathing and laundry may go down the drain, but it doesn’t need to go to waste. It can be put to good use for landscape irrigation — safely and legally.
Up to 40 percent of indoor water can be captured and reused as graywater. Graywater is gently used water from bathroom sinks, showers, tubs, and washing machines. It is not water that has come into contact with feces, either from the toilet or from washing diapers.
Graywater may contain traces of dirt, food, grease, hair, and certain household cleaning products. While graywater may look “dirty,” it is a safe and even beneficial source of irrigation water in a yard. Keep in mind that if graywater is released into rivers, lakes, or estuaries, its nutrients become pollutants, but to plants, they are valuable fertilizer. Aside from the obvious benefits of saving water (and money on water bills), reusing graywater keeps it out of the sewer or septic system, thereby reducing the chance that it will pollute local water bodies. Reusing graywater for irrigation reconnects urban residents and backyard gardens to the natural water cycle.
The easiest way to use graywater is to pipe it directly outside and use it to water ornamental plants or fruit trees. Graywater can also be used to irrigate vegetable plants as long as it doesn’t touch edible parts of the plants. In any graywater system, it is essential to use “plant friendly” products, those without salts, boron, or chlorine bleach. The build-up of salts and boron in the soil can damage plants.
Washing machines are typically the easiest source of graywater to reuse because graywater can be diverted without cutting into existing plumbing. Each machine has an internal pump that automatically pumps out the water which can be used to pump the graywater directly to your plants.
- puts less strain on treatment systems and septic tanks
- reduces energy and chemicals used for wastewater treatment
- recharges groundwater and reclaims nutrients
Graywater systems are regulated under the California Plumbing Code. EBMUD offers a rebate of up to $50 per graywater system 3-way diverter valve.
There is growing evidence that graywater systems are an accepted option for landscape irrigation and an important water conservation program component. Occupants of 11,000 new single-family houses under construction near Tracy will have separate graywater plumbing, with two underground tanks and a recycling unit about half the size of a refrigerator turned on its side. The system adds $8,000 to $10,000 to the cost of each house, but will be amortized in a monthly bill and partially offset by savings in water and sewer charges. The water can be used to flush toilets but mainly will go outdoors for landscaping and car washing. The system does not include toilet, so-called black water, but still can reduce household use by an estimated 40 to 60 percent.
This article first appeared in the May 18, 2016 issue of the Rossmoor News, author Barb Coenen