In Focus
Pure Water Los Angeles: L.A.’s Journey Toward a New and Sustainable Water Supply
by Lesly Figueroa
A lasting legacy may stem from a brilliant idea developed in response to a great challenge. Employees within the various departments of the City Los Angeles have always been able to do this through the delivery of innovative ideas when it was needed most - whether it was managing rapid growth, air pollution, a timely response to natural disasters or even putting on two Olympic games. Today, those challenges come from climate change, seismic risks, and other factors threatening our water security. One of those ideas poised for a lasting and positive impact is none other than Pure Water Los Angeles, a collaborative initiative designed to develop a new local drinking water supply. This major undertaking aims to address the effects of climate change and water scarcity to enhance water independence through purified, recycled water.
What is Pure Water Los Angeles?
Pure Water Los Angeles is the City of Los Angeles’ new local drinking water supply developed through a collaboration between the Los Angeles Department of Water and Power (LADWP) and Los Angeles Sanitation and Environment (LASAN) to purify recycled water through an advanced water purification system.
Purified recycled water will be produced from wastewater treated at the Hyperion Water Reclamation Plant located in Playa Del Rey. When the project is completed, the Hyperion Water Reclamation Plant will provide up to 230 million gallons per day of purified recycled water. This new local water supply will increase and optimize the city’s local supplies and support the transition to 70 percent local water.
An engineering project of this scale has not been attempted since the original Los Angeles Aqueduct was completed in 1913. Pure Water Los Angeles is a combination of investments in infrastructure, communities, and building a legacy of water security in Los Angeles.
“We’re preparing future generations for a new era of water resources and management that will create new jobs and protect the environment. Our success relies on our ability to innovate and achieve water resiliency. Pure Water Los Angeles will benefit everyone in the City of Los Angeles.”
Anselmo Collins, Senior Assistant General Manager – Water System
Why Does L.A. Need Purified Recycled Water?
The City of Los Angeles has purchased imported water for decades from the Bay Delta and the Colorado River Aqueduct and has historically transported water from the Eastern Sierra via the Los Angeles Aqueduct for over 100 years.
Climate uncertainties and disasters can pose threats to our water deliveries from these sources, as the arid Southwest grapples with overallocation of water rights. Additionally, earthquakes pose a threat to the infrastructure of the three major aqueducts. New local water from Pure Water Los Angeles will diversify our water resources in an affordable manner and ensure an equitable and sustainable future for the region.
Los Angeles is part of the growing effort to purify recycled water through various initiatives. Pure Water programs are now becoming increasingly common in the water utility sector. For example, Orange County has been incorporating purified recycled water through indirect potable reuse into its supply since 2008. Monterey, CA has been doing it since 2020.
How Does Advanced Treatment Work?
Purified recycled water is the result of providing additional steps past the existing wastewater treatment process, known as full advanced treatment. This type of treatment in water recycling refers to processes applied after the conventional primary and secondary wastewater treatment. This secondary effluent, or wastewater, is currently sent to the Santa Monica Bay. Pure Water Los Angeles will build and operate membrane bioreactors to modernize the existing secondary treatment, to produce high quality source water for advanced treatment.
With the inclusion of advanced treatment to produce purified recycled water, this water can then be added to our drinking water in full compliance with the State of California’s strict regulations. Pure Water Los Angeles will meet or exceed public health and safety standards.
Photo by City of Los Angeles
The exact method Pure Water Los Angeles will choose to deliver recycled water into our water supply is still in discussion. In California, both Indirect Potable Reuse (IPR) and Direct Potable Reuse (DPR) employ advanced treatment processes to purify wastewater that meets safe drinking water standards. However, DPR requires stringent treatment due to the lack of an environmental buffer, such as a groundwater basin. Both DPR and IPR methods use a "treatment train" approach, typically involving ultrafiltration, reverse osmosis, and ultraviolet light/advanced oxidation. DPR goes further and requires additional processes like ozonation and biologically active filtration, a multi barrier water treatment process that controls taste and odor and ensures a higher level of pathogen and chemical removal. This additional step generates better overall water quality before it’s ready for direct drinking water distribution to customers.
IPR, widely used in Pure Water programs, differs from DPR by including groundwater replenishment. Here, purified recycled water goes through a groundwater treatment facility before distribution to customers.
Building Pure Water Los Angeles
Pure Water Los Angeles will require significant investment in infrastructure facilities for advanced water treatment. This includes an extensive pipe distribution and conveyance system, pump stations, storage tanks, well fields, direct potable reuse treatment, and groundwater treatment. At full scale, the program will require approximately 70 acres of real estate throughout Los Angeles to meet project needs.
The estimated cost is currently between $21 to $25.4 billion in 2024 U.S. dollars. The infrastructure built for Pure Water Los Angeles will be operated and maintained by both LADWP and LASAN, staff creating economic opportunities for Angelenos.
Pure Water Los Angeles will deliver a wide range of regional benefits to Los Angeles. Investments in communities, protection of the Santa Monica Bay, and the creation of new and well-paid sustainable jobs are only a few of the benefits that will contribute to the overall success of the program.
A Lengthy, but Worthy Planning Process
LADWP and LASAN completed complementary planning documents, the Master Plan and the Hyperion Program Implementation Plan, to establish a planning framework for Pure Water Los Angeles.
The project will require the preparation of the Programmatic Environmental Impact Report (PEIR), pursuant to the California Environmental Quality Act (CEQA). The PEIR process will assess potential environmental impacts and lay out alternatives to consider for the project. LADWP staff is committed to ensuring opportunities for public engagement and input throughout the entire planning process. The Final PEIR will inform ultimate decisions and guide the implementation of Pure Water Los Angeles.
To complement the PEIR process, the project team has put together a Stakeholder Engagement Group that holds meetings periodically to ensure public input from groups in the the community, as well as experts in their fields. Lastly, a series of virtual and in-person community meetings, along with tabling opportunities throughout the city, will help highlight the needs and concerns regarding the project.
LADWP and LASAN are committed to equity as a foundational principle of Pure Water Los Angeles. Although still under development, an equity roadmap is being designed in collaboration with community-based organizations to ensure a meaningful engagement process that is tailored to underserved communities. This approach aims to help better understand how Pure Water Los Angeles could impact underserved communities and address their specific needs or concerns.
The Foundation for a Lasting Legacy
Pure Water Los Angeles is laying a foundation for a holistic approach to managing all water resources in an integrated and sustainable way, where every drop is valued, and every community member is heard. It is one of those brilliant ideas, born to make history. It will ensure continued access to clean, safe, and reliable drinking water for all.
For more information about Pure Water Los Angeles, please visit PureWaterLosAngeles.com to dive deeper into the implementation plans and resources available.
Program Team for Pure Water Los Angeles (as of July 2025)
LADWP Water Engineering and Technical Services
Rafael Villegas Johan Torroledo Ben Tanimoto Kevin Stewart Ruwanka Purasinghe Benson Lim Brenda Mata Lluvia Lopez Weiwei Southerland Erin Maciel Andres Perez Carl Villalobos Ricardo Parra Jonathan Chan Flor Hernandez Torres
LASAN Water Recycling Implementation
Hubertus Cox Charles Senaya Nasir Emami Christina Jones Kimia Nader-Tehrani Abigail Nguyen Huy Nguyen Ogechukwu Ogbechie Joanna Vasquez Quynh Ho Manikandan Mohandas Hamed Haddad Zadegan Madai Sanchez Yoon Lee Debora Leite Mitzi Minamide
LADWP Communications and Community Affairs
Jessica Johnson Christina Holland Lesly Figueroa Emily Rose Oachs
LASAN External Affairs and Public Affairs
Nicole Benson Tonya Shelton Niesha Louis Pamela Perez Janice Murray Kenneth Jeong Marisela Reyes Cherie Byers
