California Water Boards' Annual Performance Report - Fiscal Year  2019-20 

Key Functional Categories

What We Do and How We are Doing


The Water Boards are charged with cleaning up a broad universe of contaminated sites throughout the state. These cleanup programs have been addressing pollution from former industrial activities and leaking underground petroleum tanks for many years. Site cleanup responsibilities primarily reside within four main programs at the Water Boards: the Underground Storage Tank Program, the Site Cleanup Program, the Department of Defense Program and the Land Disposal Program. These Water Board cleanup programs are charged with ensuring sites are remediated to protect the State of California’s surface and groundwater and return it to beneficial use. more...

More information on the FY 2019-20 target results and FY 2020-21 targets

Fiscal Year  2019-20 
Statewide Overview of
Water Board Cleanup Sites

Total sites requiring cleanup: 6,225
Total sites in active remediation: 1,601
Total sites closed to date: 20,761

Graph Data Reported

Groundwater and Clean Up

Underground Storage Tank Cases:

Cleanup of Contaminated Sites

Pollutants discharged above or under the ground can contaminate the soil and underlying groundwater. Contaminants in the soil can also adversely impact the health of animals and humans when they ingest, inhale, or touch contaminated soil, or when they eat plants or animals that have themselves been affected by soil contamination. Volatile organic compounds, such as many common industrial solvents, can also pose a threat to human health by volatilizing from the soil into indoor air spaces, such as living or work spaces. With the discovery of various pollutants in groundwater aquifers, many drinking water wells have been shut down due to unacceptable concentrations of contaminants. Once a groundwater supply is polluted, it is difficult and expensive to clean up. Contaminants in soil can also act as long-term continuing sources of groundwater pollution, leaching into the groundwater for years in some instances. Stormwater running over and/or eroding contaminated soil can also be a significant source of surface water pollution.

Although the primary focus of cleanup programs is the restoration of groundwater quality, they generally address all environments, including surface water, groundwater, soil, sediment, the vadose zone, and air where vapor releases may affect public health. The Water Boards oversee the investigation and cleanup of contaminated sites caused by leaking underground storage tanks or other sources of pollution to soil and groundwater, including sites at military facilities.

Leaking Underground Storage Tanks

Underground storage tanks (USTs) can leak petroleum and other hazardous substances into soil and groundwater, posing a risk to drinking water quality and human health. While State Water Board-established regulations govern the prevention of leaks from USTs, which include requirements for installation, tank construction, tank testing, leak detection, spill containment, and overfill protection), local agencies issue permits for tank operation and enforce tank testing requirements within their jurisdiction. Owners and operators of USTs must quickly report unauthorized releases to the county or Regional Water Board to minimize impacts. Upon confirming that an unauthorized discharge has polluted, is polluting, or threatens to pollute water quality, the Regional Water Board then works with the local agency to oversee the investigation and cleanup of soil and groundwater pollution at current and former UST facility sites. Although the primary focus of the program is restoration of groundwater quality, contaminated soil and sediment, as well as vapor releases, which may affect public health, are also addressed.

The majority of UST owners and operators in the State take the initiative to voluntarily comply with UST leak prevention and cleanup laws and regulations. If compliance is not voluntarily achieved, due to lack of information, neglect, or deliberate intent, the State Water Board works with other agencies to enforce the requirements.

Site Cleanup

Sources other than underground storage tanks can also pollute soil and groundwater. Contaminants such as solvents and metals may be released as a result of spills, current and former industrial facility operations, and commercial facility operations, such as dry cleaners. The State and Regional Water Boards oversee the investigation and cleanup of these sites. As with USTs, dischargers generally perform cleanup on a voluntary basis. New contaminated sites are discovered as a result of recent spills, property transactions, or nearby environmental investigations.

The environmental cleanups at various contaminated sites can range in complexity from simple cleanups to complex federal Superfund cleanups. A complex cleanup process can involve multiple Water Board regulatory programs, such as USTs, land disposal, stormwater, and wastewater and other local, State and federal agencies.

Military Sites

At Department of Defense (DoD) facilities, leaking underground and aboveground storage tanks, as well as solvents and other chemicals used in on-base activities, have contaminated soil and groundwater. The State and Regional Water Boards work with DoD, through a cooperative agreement, to oversee the investigation and remediation of water quality issues at active and former military facilities. Like other contaminated sites, the cleanups at various DoD facilities can range from a few UST cleanups to complex federal Superfund cleanups.

The State Water Board administers the DoD program while the Regional Water Boards provide regulatory oversight at DoD facilities. The California Department of Toxic Substances Control, which administers the cooperative agreement, is the lead regulatory agency for some military sites and shares the lead with the Regional Water Boards for others. The USEPA is the lead at federal Superfund sites.