Gray water's time in the sun
Updated 6:10 pm, Monday, February 24, 2014
"Can Anybody Save California?" That was the headline of a Politico story earlier this month about our state's water crisis. Predictions of apocalypse are not uncommon when it comes to water in the West, and yet buried in the same story was a major part of the answer; notwithstanding an additional 4 million residents, demand for water in Southern California has not risen since 1990 - due largely to conservation measures. Gray water use, in particular, may be approaching its moment in the sun.
For those who recall the drought of the 1970s, stories of people capturing their shower water in buckets and hauling it out to dribble on shriveled gardens still resonate. We've come a long way since then, most critically in light of 2009 legislation setting standards for gray water use, and clarifying when such systems are legal and safe. Gray water is basically the soapy water from household laundries, showers, baths and non-kitchen sinks. With the right soap products, much of this water can be repurposed outdoors with significant water and energy savings, as well as benefits for plants themselves.
The ability of conservation technology to support growing city populations and economic development is surprisingly unsung. Efficient water use is not merely a matter of "personal virtue," as a former vice president once scoffed about energy conservation. Investing in water efficiency may be among California's, and the West's, most effective and strategic paths to water resilience in the face of climate change.
Even though water conservation programs over the last several decades have demonstrated success, Californians still use on average about 192 gallons of water per person each day, and this number climbs much higher in many areas. The state estimates that landscape irrigation accounts for about 4 million acre-feet each year, or roughly 43 percent of total urban demand - all industrial, commercial, institutional and residential water use combined.
This has significant implications for gray water and other outdoor water-saving technology. According to a 2009 UCLA study, if 10 percent of Southern California homes reused their gray water, the volume of water saved could be equivalent to the capacity of a large seawater desalination facility. In general, about 50 percent of all household wastewater produced could be diverted as gray water, and some estimates are as high as 80 percent.
The barriers to wider application of gray water at this point are largely logistical and financial. The technology and the legal foundation are in place, but finding professionals who specialize in gray water systems, figuring out the permit requirements and navigating the available support programs can be daunting. For this reason, our organization, WaterNow, is developing gray water pilot programs in several California communities to address these issues, with the goal of helping to substantially increase use of these systems.
Our first initiative is the Marin County Sustainable Water Program, where we are working with the county, local wastewater agencies, cities, builders, landscapers, nonprofits and others to expand use of sustainable water strategies, but most specifically gray water. Our goal is to build a program that makes installation of these systems easy, accessible and affordable and can be replicated in communities statewide. This new effort, just launched as the drought was declared, will get moving in the next few months with trainings, permit information, financing mechanisms and public outreach efforts.
Even in a time when drought concerns are dominating the news, water is still - in most urban areas of the state - reliable and inexpensive, usually costing a fraction of a cent per gallon. Indeed, a Public Policy Institute of California study conducted in September reflects California's mixed feelings about water and what to do about it. Only 2 percent of Californians felt that water was the most important issue facing people in the state. Yet more than half the population believed that water supply for their part of the state will be somewhat or very inadequate within the next 10 years. Sparse rainfall and snowpack this year means those future concerns have arrived now.
California, like the rest of the nation, needs a full complement of tools to create a more resilient water future, as there is no one best solution. But as we proceed, gray water reuse and other efficiency technologies, especially those focused on outdoor use, should have a seat at the policy table.
"Can Anybody Save California?" The answer, of course, is - we all can.
What is gray water?
Gray water is defined by California law as wastewater from laundries, showers and bathroom sinks, but not wastewater from dishwashers or kitchen sinks or toilets. Gray water cannot contain hazardous chemicals or human or food waste.
How can I use gray water?
-- In single-family homes, gray water can be used for outdoor irrigation, although not for root crops or edible parts of food that touch the soil.
California recognizes three categories of gray water systems:
-- Laundry to landscape
-- Simple systems with capacity to discharge 250 gallons per day or less.
-- Complex systems with capacity to discharge more than 250 gallons per day.
For each, the gray water must be contained on the site where it is generated and must be directed to an irrigation or disposal field. Gray water cannot be allowed to pond. To avoid cross contamination, gray water systems must be designed to avoid backflow back into the potable water system.
Do gray water systems require a permit?
-- Laundry-to-landscape systems do not require permits under the state rules. Both simple and complex systems require permits from local authorities.
How much do gray water systems cost?
-- There is not a great deal of reliable data, but Greywater Action, a nonprofit organization, has found that cost varies by the complexity of the system, the size of the landscape involved and whether the installation is done by the building owner or a professional. Its experience indicates that laundry-to-landscape systems can cost about $250 to $2,000; branched-drain systems from about $400 to $3,000; pumped systems from about $600 to $3,000; and certain high-tech, residential gray water systems can cost $5,000 to $10,000.
Sources: California Housing and Community Development Code Title 24, Part 5, Chapter 16 A; Greywater Action.
Drought is a major concern today in California, but increased concern about efficient water use will be the concern tomorrow and into the future. In coming weeks, Insight writers will address a series of questions about water use in California. We start today with: Do you know how much water you use and for what?
The Association of California Water Agencies offers this online tool to help you figure that out.
Cynthia Koehler and Audrey Finci, with Kathleen Moazed, are co-founders and principals of WaterNow ( www.waternow.org), a nonprofit dedicated to promoting sustainable water solutions in California and throughout the West.