Building Local Supplies

Native plant garden weymouth

Think Regional, Act Local

Metropolitan’s role in the region has evolved over time. We are builders and planners. We brought water to Southern California, and we look today at the possibilities of local supply development to complement our imported supply investments. Our support of conservation and diverse local resource programs like water recycling, desalination, groundwater recovery and storage have provided over 7 million acre-feet to the region’s resource mix and increased our resiliency and reliability. Local resources are regional resources because they offset regional imported water demands.

It’s not an either-or situation: we’re developing local resources while shoring up our imported supplies. Each piece of our supply portfolio depends on the other. One is insurance against the other’s vulnerabilities. When imports are challenged by drought cycles or natural disasters, local resources and conservation programs can ease the burdens of import demands. In turn, high quality imported supplies are necessary for recycling and groundwater replenishment programs. Working together, these sources provide Southern California with reliable water. Having a mix of water resources to draw from has protected the region from the impact of drought cycles and climate change.

Biomembrane

Local Supplies for Regional Reliability

When a local supply is developed, whether it is in Ventura, San Diego, or any community in between, all Southern California benefits. Our regional cooperation and interdependence mean one community’s recycling or groundwater cleanup project decreases the burden on Metropolitan’s system as a whole. That reduces operating costs, frees up conveyance capacity to benefit all system users and helps the region adapt to climate change. That is why Metropolitan supports and incentivizes several beneficial programs and initiatives that help the region act locally. We have invested $1.6 billion in these programs to date. For a rundown of achievements, click here and for the full Achievement Report click here.

The numbers tell a success story. In the 1990s, nearly 60 percent of Metropolitan’s supply portfolio was made up of imported resources from the Colorado River and our contract with the State Water Project. The balance was from local resources. A shift in the supply paradigm shows a 2035 mix of about 36 percent imported supply and 64 percent local resources.

Local Supply Target

Local Resources

Ensuring reliable water for Southern California requires investing in local water supplies from diverse sources and widespread conservation.

Water treatment

Recycled Water

Water is too precious a resource to use just once. Recycled water would reduce reliance on imported water supplies, reuse water currently sent to the ocean, and recycle cleaned wastewater to create a drought-resilient readily available supply that could be used for groundwater replenishment, landscape irrigation or industrial purposes.

Metropolitan has historically supported recycled water projects developed by others through our Local Resources Program, but with hotter temperatures and drier conditions, it’s going to take all of us working together to find new and innovative ways to protect and maximize our water. That is why Metropolitan, and the Los Angeles County Sanitation Districts are advancing their legacies of being good water stewards with a partnership to develop a new source of local water through a regional recycled water project called Pure Water Southern California. If fully realized, Pure Water Southern California would produce up to 150 million gallons of water daily – enough water for about 500,000 homes. It would be one of the largest advanced water treatment plants in the world. The program is currently operating a 500,000-gallon-per-day demonstration facility to verify its innovative processes, which could improve efficiencies and reduce costs in water recycling. This would be a new source of water for up to 15 million people.

 

Learn more about The Pure Water Southern California

 

To further support local water supplies Metropolitan’s board approved a $3 million annual budget for the On-site Retrofit Program, which provides financial incentives for the conversion of potable irrigation and industrial systems to recycled water. Incentives can help cover the costs of project design, permitting, construction costs associated with the retrofit, connection fees and required recycled water signage.

Read more about Metropolitan's On-site Retrofit Program.

Milestones in Recycled Water Use

The past five decades have seen recycled water use in Southern California grow rapidly, for both irrigation and groundwater replenishment.

Here's a look at its history in the region, from the first recycled water plant to the large recycling water projects we see today.

 

1962

The Sanitation Districts’ Whittier Narrows Water Reclamation Plant becomes the first plant in the U.S. intentionally designed to recycle water, using it to recharge groundwater basins.

 

1970s

As Southern California’s population grows, recycled water lines are constructed alongside new development to irrigate schoolyards, parks and golf courses.

 

1975

Water Factory 21 begins purifying wastewater in Orange County and using it to replenish and protect groundwater from seawater intrusion. Becomes first plant in the world to use reverse osmosis.

 

1980s

Wastewater treatment plants add processes to produce more recycled water. Purple pipes are adopted as industry standard to distinguish recycled water for irrigation, firefighting and industrial use.

 

1995 to 2005

Several new water recycling facilities are built that use reverse osmosis. The resulting water is used for groundwater recharge and industrial use.

 

2008

Orange County embarks on the largest water reuse project of its kind in the world, eventually purifying 130 million gallons of water daily to replenish groundwater supplies used for drinking. Becomes the gold standard for water recycling.

 

2014

The city of San Diego advances a water recycling program that for the first time in California would use purified recycled water to fill a drinking water reservoir.

 

TODAY

Water agencies from Ventura to San Diego continue to take steps toward implementing large recycling projects. The Regional Recycled Water Program will take the rapid growth of recycled water use in Southern California even farther.

Local resource project

Desalination

Metropolitan has explored seawater desalination as a potential new supply since the 1960s, and we even developed and piloted our own thermal distillation technology.  

While desalination technology has been used to treat and recover brackish groundwater for decades, the cost of treating seawater was not historically competitive with other resources. In the past 10 years, rapid improvements in membrane performance, energy recovery technology and process design have lowered seawater desalination costs, making it, in some cases, competitive with other new supply options.

Since 2001, Metropolitan has provided financial incentives for our member agencies to develop local seawater desalination projects, and seawater desalination became part of of our Local Resources Program in 2014.

Groundwater replenishment

Groundwater Recovery

Groundwater provides more than 35 percent of Southern California's drinking water, making groundwater replenishment and storage programs critically important. Groundwater wells sometime become unusable because of contamination or increased salinity. This leaves water agencies with a choice – they can rely more heavily on imported supplies as a replacement or they can recover the groundwater by building treatment facilities to remove contaminants or salt. Although Metropolitan does not own or manage groundwater basins in Southern California, we play a critical role as the region's supplemental water supplier. We help replenish the basins and financially support groundwater recovery projects that treat groundwater. 

Metropolitan also works with local agencies to store imported surface water in groundwater basins for use in times of shortage under conjunctive-use agreements. These agreements create flexible ways to manage water resources. Other management tools include water exchanges and transfer programs that help ensure future water supplies for the region.

Rio Hondo spreading grounds basin

Stormwater

In 2020, Metropolitan launched two pilot programs to better understand the costs and benefits of stormwater capture, yield and use. One program looks at opportunities to capture stormwater for direct use. The other explores stormwater capture for groundwater recharge. Together, Metropolitan invested $12.5 million in these programs. The data collected will help Metropolitan evaluate the water supply benefits of stormwater capture and provide guidelines for future funding strategies.

Woman in rouse garden

Conservation

A growing slice of Metropolitan’s reliability equation is water conservation. Through myriad initiatives — including financial incentives and partnerships with member agencies, local communities, schools, businesses and diverse organizations — conservation has become a way of life in Southern California. 

Over the past 40 years, Metropolitan has driven innovation, evolved markets and influenced consumer decision-making to increase water-use efficiency. Catalysts such as direct rebates, outreach and education, new technology support, advocacy for new building codes and standards, and development of strategic alliances have contributed to positive lasting change.

Visit bewaterwise.com and SoCalWater$mart to learn more about Metropolitan’s residential and commercial rebate programs and incentives and other conservation programs. 

We also support innovative conservation efforts in business with research partnerships and programs like the Water Savings Incentive Program. This regional pay-for-performance initiative is available to all commercial, industrial, institutional, agricultural and large landscape consumers with qualifying projects that focus on water-use efficiency within Metropolitan’s service area. 

The Innovative Conservation Program offers competitive grant funding to evaluate water savings and reliability of devices, technologies and strategies. More detailed information about these funding programs is available here. 

Since 2009, Metropolitan and local water agencies have maintained a Long-Term Conservation Plan that supports state legislation aimed at reducing water use. Southern California met the plan’s goal of reducing per capita water consumption by 20 percent by 2020. The lasting changes are clear today – consumers’ values, behaviors and preferences for water-efficient devices have led to significant reductions in water consumption.

Future Supply Actions

Metropolitan is also investing in research to develop future local water supplies through innovative approaches. Through the Future Supply Actions Funding Program, Metropolitan funds member agency pilot projects and technical studies aimed at increasing the potential of recycled water, stormwater, groundwater and seawater desalination. Metropolitan has so far invested $6.5 million in more than two dozen studies.