Onsite Wastewater Treatment Systems (OWTS) Policy: Water Quality Control Policy for Siting, Design, Operation, and Maintenance

California State Water Resources Control Board (SWRCB) | June 19th, 2012

The purpose of this Policy is to allow the continued use of OWTS, while protecting water quality and public health. This Policy recognizes that responsible local agencies

The purpose of this Policy is to allow the continued use of OWTS, while protecting water quality and public health. This Policy recognizes that responsible local agencies can provide the most effective means to manage OWTS on a routine basis. Therefore as an important element, it is the intent of this policy to efficiently utilize and improve upon where necessary existing local programs through coordination between the State and local agencies. To accomplish this purpose, this Policy establishes a statewide, risk-based, tiered approach for the regulation and management of OWTS installations and replacements and sets the level of performance and protection expected from OWTS. In particular, the Policy requires actions for water bodies specifically identified as part this Policy where OWTS contribute to water quality degradation that adversely affect beneficial uses. This Policy only authorizes subsurface disposal of domestic strength, and in limited instances high strength, wastewater and establishes minimum requirements for the permitting, monitoring, and operation of OWTS for protecting beneficial uses of waters of the State and preventing or correcting conditions of pollution and nuisance. And finally, this Policy also conditionally waives the requirement for owners of OWTS to apply for and receive Waste Discharge Requirements in order to operate their systems when they meet the conditions set forth in the Policy. Nothing in this Policy supersedes or requires modification of Total Maximum Daily Loads or Basin Plan prohibitions of discharges from OWTS. This Policy also applies to OWTS on federal, state, and Tribal lands to the extent authorized by law or agreement.

Overview of Greywater Reuse: The Potential of Greywater Systems to Aid Sustainable Water Management

Pacific Institute | November 18th, 2010

As pressures on freshwater resources grow around the world and as new sources of supply become increasingly scarce, expensive, or politically controversial, efforts are u

As pressures on freshwater resources grow around the world and as new sources of supply become increasingly scarce, expensive, or politically controversial, efforts are underway to identify new ways of meeting water needs by expanding the usefulness of alternative sources of water previously considered unusable. Greywater reuse is one such strategy. Greywater is the relatively high-quality wastewater generated from household uses like bathing and washing clothes. When reused either onsite or nearby, greywater has the potential to reduce the demand for new water supply, reduce the energy and carbon footprint of water services, and meet a wide range of social and economic needs. In particular, the reuse of greywater can help reduce demand for more costly high-quality potable water. The 2010 report Overview of Greywater Reuse: the Potential of Greywater Systems to Aid Sustainable Water Management analyzes how, as a key strategy that reduces demand, greywater reuse can improve the resilience of water systems to the impacts of climate change. It also serves as a relatively secure or drought-resistant source of water supply because presumably greywater generated from showers and washing machines will continue, if at a reduced rate. And in helping displace demand for water, greywater reuse can help reduce conflicts over water and reduce the demand for new water supply projects as a result of climate change. The research shows that when the systems are designed and implemented properly, possible public health concerns with using different water qualities can be addressed. As greywater reuse becomes more widely adopted, regulations can be put in place to ensure that water quality is appropriately matched to water need. This paper provides a broad overview of the state of greywater implementation and policy, with a special emphasis on the Middle East. It examines the potential of greywater to reduce the water and energy intensity of water uses, and it analyzes key issues that must be addressed for greywater to be accepted, and implemented, at larger scales.

Policy for Water Quality Control for Recycled Water (Recycled Water Policy)

California State Water Resources Control Board (SWRCB) | June 21st, 2013

The purpose of this Policy is to increase the use of recycled water from municipal wastewater sources that meets the definition in Water Code section 13050(n), in a manne

The purpose of this Policy is to increase the use of recycled water from municipal wastewater sources that meets the definition in Water Code section 13050(n), in a manner that implements state and federal water quality laws. The State Water Board expects to develop additional policies to encourage the use of stormwater, encourage water conservation, encourage the conjunctive use of surface and groundwater, and improve the use of local water supplies. When used in compliance with this Policy, Title 22 and all applicable state and federal water quality laws, the State Water Board finds that recycled water is safe for approved uses, and strongly supports recycled water as a safe alternative to potable water for such approved uses.

Pure Water Southern California

Metropolitan Water District of Southern California (MWD) | March 29th, 2024

Pure Water Southern California Volume 1 - Draft Enviornmental Impact Report

Metropolitan Water District of Southern California (MWD) | May 14th, 2025

Pure Water Southern California (Pure Water) is a proposed partnership between The Metropolitan Water District of Southern California (Metropolitan) and the Los Angeles Co

Pure Water Southern California (Pure Water) is a proposed partnership between The Metropolitan Water District of Southern California (Metropolitan) and the Los Angeles County Sanitation Districts (Sanitation Districts) to beneficially reuse cleaned wastewater that is currently being discharged to the Pacific Ocean from the Sanitation Districts’ A.K. Warren Water Resource Facility (Warren Facility) in the City of Carson. At full buildout, Pure Water would purify up to 150 million gallons per day (MGD), making it one of the largest programs of its kind in the world. Implementation of Pure Water would provide regional benefits to all Metropolitan member agencies by: (1) reducing reliance on imported water; (2) diversifying locally available supplies; (3) improving resilience to climate change and other stressors; and (4) enhancing operational reliability and flexibility.  This Environmental Impact Report (EIR) assesses the potential environmental effects of Pure Water and was prepared in accordance with the California Environmental Quality Act (CEQA) and its implementing guidelines. Metropolitan is serving as the lead agency in preparation of this EIR; the Sanitation Districts are serving as a responsible agency. The EIR is intended to inform governmental decisionmakers and the public about the potential environmental impacts associated with construction and operation of Pure Water, and to identify ways that potentially significant impacts can be avoided or reduced by making changes to the program, selecting an alternative, and/or adopting feasible mitigation measures.  Click here for appendices.

Recycled Water Research Needs in California: Monitoring and Treatment Performance for Constituents of Emerging Concern

California State Water Resources Control Board (SWRCB) | April 4th, 2017

The California State Water Resources Control Board (State Water Board) held a workshop on October 27-28, 2015 in Costa Mesa focused on the state of the science, monitorin

The California State Water Resources Control Board (State Water Board) held a workshop on October 27-28, 2015 in Costa Mesa focused on the state of the science, monitoring techniques, and water treatment reliability for constituents of emerging concern (CECs) in recycled water. The goal of the workshop was to help the State Water Board identify knowledge gaps to identify and prioritize CEC monitoring and treatment activities that will ensure water supplies from recycled water, including potable reuse, are protective of public health and the environment. The workshop included presentations from experts regarding monitoring and treatment performance for CECs, as well as breakout sessions intended to review and discuss the most important CEC research needs. At the conclusion of each day, a summary of recommendations based on the breakout discussions was developed by the participants. Below are general takeaway messages developed during the workshop. These messages reflect discussions at the workshop and are not intended to represent the views of all participants.

Reimagining Water Infrastructure in a Changing California

American Water Resources Association (AWRA) | April 15th, 2023

For much of the 20th century, California’s water supply strategy has relied on building large reservoirs and conveyance systems to store and divert surface water and dr

For much of the 20th century, California’s water supply strategy has relied on building large reservoirs and conveyance systems to store and divert surface water and drilling ever deeper wells to tap declining aquifers. This approach has brought many benefits but has also come at great social, economic, and environmental costs. Moreover, these traditional water supplies are tapped out. Even in wet years, the state’s major rivers are overallocated and major aquifers severely overdrafted. Dry years intensify these issues. Persistent water challenges, the severe drought, and the intensifying effects of climate change highlight the vulnerability of California’s water systems and the need for new approaches.

Salt and Nutrient Management Plan Santa Clara River Valley East Subbasin

California State Water Resources Control Board (SWRCB) | October 25th, 2016

In accordance with the State Water Resources Control Board’s (SWRCB’s) Recycled Water Policy, the Upper Santa Clara River Integrated Regional Water Management Group

In accordance with the State Water Resources Control Board’s (SWRCB’s) Recycled Water Policy, the Upper Santa Clara River Integrated Regional Water Management Group (IRWMG), which is comprised of Castaic Lake Water Agency (CLWA), City of Santa Clarita, CLWA Santa Clarita Water Division (SCWD), Los Angeles County Flood Control District (LACFCD), Newhall County Water District (NCWD), San Gabriel & Lower Los Angeles Rivers and Mountains Conservancy, Santa Clarita Valley Sanitation District (SCVSD) and Valencia Water Company (VWC), have entered into a Memorandum of Understanding (MOU) to prepare a Salt and Nutrient Management Plan (SNMP) for the Santa Clara River Valley East Groundwater Subbasin (East Subbasin). This group of agencies, collectively known as the SNMP Task Force (Task Force) and facilitated by the CLWA, have directed the preparation of this SNMP, which was prepared using guidance set forth by the Los Angeles Regional Water Quality Control Board (LARWQCB). The purpose of this SNMP is to determine the current (ambient) water quality conditions in the East Subbasin and to ensure that all water management practices, including the use of recycled water, are consistent with water quality objectives. This SNMP is intended to provide the framework for water management practices to ensure protection of beneficial uses, and allow for the sustainability of groundwater resources consistent with the Water Quality Control Plan Los Angeles Region (Basin Plan). Additionally, compliance with the California Environmental Quality Act (CEQA) and approval by LARWQCB staff is required. As part of the SNMP, a monitoring plan has been developed for the East Subbasin which identifies key monitoring locations within each subunit for both surface water and groundwater.

San Gabriel Valley Groundwater Basin Salt And Nutrient Management Plan

Publisher not available | May 31st, 2016

Study to Evaluate Long-Term Trends and Variations in the Average Total Dissolved Solids Concentration in Wastewater and Recycled Water

Southern California Salinity Coalition | March 30th, 2018

This report was funded by the Southern California Salinity Coalition (SCSC). SCSC and its member agencies are dedicated to managing salinity in the water supplies, waste

This report was funded by the Southern California Salinity Coalition (SCSC). SCSC and its member agencies are dedicated to managing salinity in the water supplies, wastewater, and recycled water. Member agencies include Eastern Municipal Water District (EMWD), Inland Empire Utilities Agency (IEUA), Metropolitan Water District of Southern California (MWDSC), Orange County Sanitation District (OCSD), Orange County Water District (OCWD), San Diego County Water Authority (SDCWA), Sanitation Districts of Los Angeles County (LACSD), and Santa Ana Watershed Project Authority (SAWPA). Daniel B. Stephens & Associates, Inc. (DBS&A) performed the analysis and is submitting this technical memorandum to address the research questions posed by SCSC and its member agencies. The 2011 to 2016 drought in California, in conjunction with unprecedented statewide conservation legislation, caused several member agencies to face challenges meeting regulatory water quality standards for the salinity of discharge water from wastewater treatment plants (WWTPs). In particular, total dissolved solids (TDS) concentrations have increased, while the operation of WWTPs have remained consistent with prior years. Figure ES-1 is a typical example of TDS trends for WWTPs in Southern California.