With its semi-arid climate and little native water resources, the City of Los Angeles relies upon importing water from hundreds of miles away—from the Eastern Sierra, the Sacramento-San Joaquin Delta (Delta), and the Colorado River—to support its population. However, recent regulatory restrictions on importing water from the Delta, coupled with environmental restoration in the Eastern Sierra, have triggered the need to develop more locally sustainable water resources.
Among the stresses on Los Angeles' water supply are the lowest snowpack in the Eastern Sierra and the driest weather recorded in 2007, and a 2008 Federal Court ruling that limited exports from the Delta by as much as one-third to protect the Delta smelt, an endangered fish. Added to that is the loss of a significant portion of the San Fernando Basin as a water source because of widespread contamination to the groundwater.
In May 2008, the City of Los Angeles released a Water Supply Action Plan titled “Securing L.A.’s Water Supply", to increase local water resources and ensure a reliable, sustainable water supply for Los Angeles. The program’s goal is to achieve additional water supplies of 50,000 acre feet per year (AFY) through recycling, and 50,000 AFY through conservation (1 acre foot is a unit of volume used in reference to large-scale water resources, and equals approximately 325,851 gallons). Other ongoing water supply initiatives include enhancing stormwater capture, accelerating cleanup of the San Fernando Groundwater Basin, expanding groundwater storage, developing standards for treating graywater, and pursuing sustainable building practices.
Under this program, the LADWP invests approximately $100 million in water recycling, stormwater capture, and water conservation each year, approximately 10% of the Water System’s annual budget.
Since the release of “Securing L.A.’s Water Supply”, there have been significant achievements in local resource development. However, there is the potential for much more. For example, nearly 50% of single-family residential water use is outdoors for landscape irrigation, and much of that is to maintain turf. There is much potential to reduce outdoor water use overall and a significant potential for household graywater reuse.
Increase Water Conservation
The water conservation effort and ethic in Los Angeles is unrivaled; water use today is lower than usage 40 years ago, despite an increase in population of more than 1.3 million people. In a time when water resources are scarce throughout the state, Los Angeles has taken the lead and continues to set an example of how to conserve water and maintain a sustainable water supply. LADWP’s strategy builds on significant investments made since the early 1990s, increasing water conservation today by targeting reductions in outdoor water use and enhancing indoor water savings through new technology.
From June 2009, when the city instituted mandatory water conservation, through August 2010, LADWP customers reduced their water use by over 19%, saving more than 50 billion gallons. This represents enough water to serve the entire populations of Glendale, Burbank, Santa Monica, Long Beach, and Beverly Hills for a year! This accomplishment was driven by an extraordinary level of conservation among customers, especially single-family residential customers who cut their usage by nearly a quarter, and government customers who cut water use by over 30%. As has been demonstrated repeatedly, LADWP customers are among our most effective conservation tools.
For more information, go to
Maximize Recycled Water
LADWP is taking actions to expand recycled water use for landscaping, industrial, and environmentally beneficial uses in Los Angeles to offset the need for imported water. The initial goal is to deliver 50,000 AFY of recycled water, increasing the amount of recycled water to 6% of the city’s water supply.
To facilitate the expansion of recycled water, the LADWP is developing a Recycled Water Master Planning Document Feasibility Study, which will identify projects to meet the goal of 50,000 AFY of recycled water usage. These projects include expansion of the recycled water distribution system, also known as “purple pipe”, for industrial, irrigation, and environmentally beneficial uses. The initial goal is to achieve 35,000 AFY for these purposes. The remaining 15,000 AFY will be saved or offset through a groundwater replenishment program. This program, which is part of the feasibility study, utilizes advanced treatment technologies such as reverse osmosis, micro-filtration, advanced oxidation, and ultra-violet disinfection. The purified recycled water will be spread into catch basins to recharge the San Fernando Groundwater Basin. This effort also includes pilot testing the advanced treatment technologies and process for up to three years so that the treatment is optimized and most effective.
In addition, the feasibility study is evaluating opportunities for satellite treatment facilities, upgrades and/or expansion at the Harbor, Hyperion, Donald C. Tillman, and Los Angeles-Glendale Treatment Plants, increasing system reliability, and partnerships with other agencies and cities to maximize recycled water use. LADWP is also evaluating the use of advanced treatment technologies at the Donald C. Tillman Water Reclamation Plant. These technologies include micro filtration, reverse osmosis, oxidation, hydrogen peroxide, and ultra violet light.
For more information, go to
Enhance Stormwater Capture – Real World Demonstrations
LADWP has teamed up with the Los Angeles County Flood Control District, the City of Los Angeles Bureau of Sanitation, and TreePeople to develop and implement cost-effective ways to capture, store, and reuse stormwater. The strategy focuses on increasing groundwater recharge by retrofitting the Big Tujunga Dam; reconstructing Hansen, Tujunga, and Pacoima Spreading Grounds and other large-scale projects; and working with other City Departments on smaller-scale projects. These projects are expected to increase stormwater capture by over 20,000 AF each year.
LADWP is also involved in numerous smaller scale pilot projects. Examples are the Elmer Avenue neighborhood retrofit in Sun Valley and a Green Alleys pilot project to demonstrate various alternatives for infiltrating stormwater.
For more information, go to
Cleanup Local Groundwater Basins
San Fernando Basin groundwater currently provides 13% of the city’s water supply. However, groundwater contamination has limited Los Angeles' use of its local water resources, putting 40% of the city's production wells out of service. Cleaning up the San Fernando Valley groundwater will help put those wells back in service and reduces the city’s reliance on imported water sources.
LADWP has implemented an interim treatment facility to restore some lost groundwater production and is conducting a Groundwater System Improvement Study to determine the extent of groundwater contamination and potential remedies. In conjunction with the United States Army Corps of Engineers, up to 40 monitoring wells will be installed.
Expanding Groundwater Storage
LADWP is investigating opportunities for increased storage of groundwater, both in the Los Angeles basin and in areas outside of the city.
For more information, go to