The federal Clean Water Act requires that states take steps to reduce pollutants below harmful levels in water bodies, including streams, rivers, lakes, and oceans. One way that pollutants can enter water bodies is through storm water runoff, which can be a significant source of water pollution, especially in urban areas. As shown in Figure 1, such pollution occurs when water from rain and melting snow flows over impervious surfaces such as paved streets and building rooftops and enters water bodies. Runoff commonly enters water bodies through storm sewer systems operated by local jurisdictions, such as cities. As it flows, the storm water collects a variety of pollutants, which the storm sewer system subsequently deposits into local water bodies. Pollutants can also enter storm drains through other means, such as runoff from the watering of lawns and gardens that contain fertilizers and pesticides.
Sources of Pollutants in Storm Water Runoff
Source: California State Auditor‑generated based on review of pollutant control plans for the Central Valley Regional Water Quality Control Board, the Los Angeles Regional Water Quality Control Board, and the San Francisco Bay Regional Water Quality Control Board.
Water bodies throughout the State are continually contaminated by various pollutants. According to a 2017 report by the State Water Resources Control Board (State Water Board), 1,357 of the 2,623 segments of water bodies in the State contain harmful levels of one or more types of pollutants, such as bacteria, metals, and pesticides. As shown in Table 1, excessive amounts of these pollutants can detrimentally affect the environment, including the health of humans and aquatic life. For example, high levels of certain types of bacteria in a water body can cause serious illnesses, such as gastrointestinal illnesses, respiratory illnesses, and skin infections in people who come into contact with the water body. People exposed to mercury by consuming fish from a polluted water body show deficits in memory, attention, and muscle control.
|Type of Pollutant
|Examples of Pollutant Sources
|Potential Harmful Effects
|Gastrointestinal and respiratory illnesses in humans
|Home and agricultural use of garden products
Source: California State Auditor‑generated based on review of pollutant control plans at the Central Valley, Los Angeles, and San Francisco Bay regional boards.
To curb the harmful effects of pollution from storm water runoff, federal law requires states to set restrictions on the pollutants that can be discharged into water bodies. It further requires local jurisdictions that discharge storm water—including cities, counties, and other public entities that operate storm sewer systems—to obtain a storm water permit from the federal government or from their state. The storm water permit contains requirements that local jurisdictions monitor their storm water discharges for pollutants and take action to reduce the pollutants to safe levels.
Almost all local jurisdictions in California that discharge storm water operate separate storm sewer systems, meaning that the system that collects storm water is separate from the sanitary sewer system that collects wastewater from homes and businesses. Certain jurisdictions, such as the city of San Francisco and a portion of the city of Sacramento, operate a combined sewer system, which collects storm water runoff, domestic sewage, and industrial wastewater in one pipe, treats it at a sewage treatment plant, and then discharges it into a water body. These jurisdictions are subject to a different type of storm water permit for these systems.
Roles and Responsibilities in the Regulation of Storm Water Pollution
The U.S. Environmental Protection Agency (USEPA) develops regulations, provides guidance, and approves states’ regulatory actions for storm water pollution. It develops maximum pollutant levels 1 in regulations and guidance for states to use when addressing storm water pollutants, and it also reviews and approves maximum pollutant levels that states develop.
In California, storm water pollution is regulated at the state level by the State Water Board and nine regional water quality control boards (regional boards), each led by its own governing board. The State Water Board provides direction and guidance to the regional boards and reviews petitions that contest regional board actions. In addition, it may issue statewide plans to address pollutant concerns that can supersede the actions of the regional boards. The State Water Board also issues permits for storm water runoff from industrial facilities, provides informal guidance on operational management to the regional boards, and encourages the sharing of best practices. For example, it facilitates quarterly roundtable meetings attended by representatives of each regional board, the State Water Board, and the USEPA. These meetings foster open discussion of water quality topics, such as maximum pollutant levels and policy planning.
The regional boards are responsible for developing and implementing maximum pollutant levels that are specific to the water bodies in their respective regions. They are also responsible for developing and managing the storm water permits for local jurisdictions with populations of 100,000 or more.2 We reviewed the regulatory activities of the State Water Board and three regional boards: the Central Valley Regional Water Quality Control Board (Central Valley), the Los Angeles Regional Water Quality Control Board (Los Angeles), and the San Francisco Bay Regional Water Quality Control Board (San Francisco Bay). The Central Valley region includes approximately 40 percent of the land in California and extends from the Oregon border to the northern tip of Los Angeles County. The Los Angeles region covers most of Los Angeles and Ventura counties and small portions of adjacent counties. The San Francisco Bay region covers most of the geographic area encompassed by the nine counties in the Bay Area. Figure 2 provides a map of the nine regions in the State.
Locations of California Regional Water Quality Control Boards
Source: State Water Board.
Regional boards adopt maximum pollutant levels based on regulation and guidance from a variety of sources. The USEPA has issued maximum pollutant levels in federal regulation for certain pollutants that exist in California water bodies. In many other cases, the State and the USEPA have provided recommended maximum pollutant levels, which the regional boards may adopt. For example, the USEPA issued recommended maximum pollutant levels for certain pesticides, but the California Department of Fish and Wildlife also issued its own recommended levels that are stricter than the USEPA levels. Central Valley adopted the state levels because they were based on more recent scientific evidence and on other evidence that considered more sensitive aquatic species.
Regional boards can also use studies of specific water bodies to justify establishing their own maximum pollutant levels, which can be more or less strict than state and federal guidance. In fact, federal regulation encourages states to use site‑specific information when developing maximum pollutant levels. For example, Los Angeles set a level for a metal pollutant in the Los Angeles River that was less strict than the level in federal regulation because studies conducted by a group of local jurisdictions, including the city of Los Angeles, demonstrated that the characteristics of the Los Angeles River made it able to tolerate higher concentrations of the metal before the water would be considered toxic. For some pollutants, the State Water Board has adopted maximum pollutant levels that the regional boards must impose. For example, the State Water Board's ocean plan sets levels for some pollutants, including bacteria, in storm water that is released into the Pacific Ocean.
Federal law also requires regional boards to develop pollutant control plans, referred to as Total Maximum Daily Loads, to improve water bodies harmed by pollution. Pollutant control plans identify the numeric goals for each pollutant that are established to achieve desired water quality. Regional boards often derive the numeric goals for specific water bodies from the maximum pollutant levels established by the State Water Board or the USEPA. We refer to these numeric goals as pollutant limits. Pollutant control plans also assign responsibility for reducing the pollutant to the sources of that pollutant, such as local jurisdictions, wastewater treatment plants, and agricultural sources. The plans also establish deadlines for such entities to meet their responsibilities. We reviewed 20 such plans that the regional boards completed between 2002 and 2016. For most of the plans, the regional boards established responsibility for municipal entities based on the concentration of the pollutant in each entity’s storm water, making each entity responsible for ensuring that the levels of pollutants in its discharged storm water are safe rather than requiring one entity to clean up the pollution and subsequently allocating responsibility to the others. For example, when developing a plan to address harmful levels of mercury in the Sacramento–San Joaquin Delta, Central Valley calculated the concentration of mercury that could safely be present in the water body. Central Valley then designated each entity responsible for ensuring that the storm water flowing from it into the water body did not exceed that pollutant limit. It is important that regional boards take great care in imposing pollutant limits on local jurisdictions, as the development and adoption of new pollutant control plans by regional boards is resource‑intensive, and that development and adoption can take several years and involve a public review process and approval from multiple governmental entities.
Comparison of the Regional Boards
Each of the three regional boards we reviewed differs in the requirements it imposes on local jurisdictions through its storm water permits. As shown in Table 2, Los Angeles has developed more pollutant control plans than either of the other two boards. In addition, these regional boards vary in the strategies their storm water permits employ to control pollutants. Central Valley’s permits generally allow local jurisdictions to prioritize and address the most critical pollutants before taking steps to address those less serious. Central Valley will prescribe specific actions that local jurisdictions must take only if they fail to follow through with the strategies they themselves develop to address their prioritized pollutants. In contrast, San Francisco Bay specifies pollution remediation methods that local jurisdictions must employ to address specific pollutants. Alternatively, Los Angeles allows local jurisdictions to prepare storm water management plans detailing how they intend to address pollutants.
|San Francisco Bay
|Area of oversight
|The entire Central Valley from the Oregon border to the northern tip of Los Angeles County
|Most of the area within Los Angeles and Ventura counties and small portions of adjacent counties
|Most of the area within the counties of Alameda, Contra Costa, Marin, Napa, San Francisco, San Mateo, Santa Clara, Solano, and Sonoma
|Number of storm water permits
|One regional permit*
|Three permits: one each for Los Angeles County, the city of Long Beach, and Ventura County
|One regional permit
|Local jurisdiction collaboration
|Local jurisdictions organized themselves into seven groups
|Most of the local jurisdictions organized themselves into 19 groups by geography
|Local jurisdictions organized themselves into six groups
|Year of most recent storm water permit
|Number of pollutant control plans‡
Source: Storm sewer permits, websites, and pollutant control plans for Central Valley, Los Angeles, and San Francisco Bay.
* Before Central Valley reissued its permit in 2016, the board issued permits individually to local jurisdictions. Some of these permits have not yet expired, so those local jurisdictions will remain under their previous permits until they expire, at which time they will have to apply for coverage under Central Valley’s 2016 permit.
† 2012 is the year of the most recent Los Angeles County permit. The 37 pollutant control plans pertain to Los Angeles County, which was the primary focus of our review.
‡ The number of pollutant control plans includes only those applicable to the urban areas regulated by the regional boards. It does not include those applicable solely to other storm water dischargers, such as industrial dischargers, because the scope of our audit focused on storm water permits issued by the three regional boards.
As shown in Table 2, local jurisdictions in the Los Angeles region must comply with significantly more pollutant control plans than local jurisdictions in other regions. This is partly because Los Angeles has a higher concentration of urbanized areas, resulting in greater pollution from storm water. Additionally, following a lawsuit initiated by two environmental groups, the USEPA entered into a consent decree, which the United States District Court approved in 1999, that required the development of pollutant control plans by 2012 for 92 groups of water bodies in the region that had harmful levels of pollutants. Central Valley and San Francisco Bay were not subject to a similar requirement, and although they must also develop pollutant control plans for their water bodies, they did not have deadlines similar to those imposed on Los Angeles. As of January 2018, Los Angeles is defending three lawsuits challenging its permit requirements. This audit report reaches no conclusions on the legal merits of the issues raised in those cases. Figure 3 illustrates the history of the Los Angeles County storm water permit, describing Los Angeles’s efforts to develop its pollutant control plans.
History of the Los Angeles Board’s Storm Water Permit for Los Angeles County
Source: California State Auditor‑generated based on review of 1999 USEPA consent decree, 1999 State Water Board order, and Los Angeles County storm water permits and pollutant control plans.
Costs for Local Jurisdictions
The effort required to comply with pollutant control plans set by regional boards can be significant, as projects may be very costly and take considerable time to complete. For example, in response to a pollutant control plan for bacteria in the Los Angeles River, the city of Los Angeles is developing a project that will capture storm water runoff from a park and reuse the water in the park. The city of Los Angeles estimates the project will cost $8.8 million and take more than three years to complete. The watershed protection program manager for the city of Los Angeles expects the annual ongoing cost for operations and maintenance for these projects will be 1 percent to 3 percent of the total construction costs.
Local jurisdictions typically incur project costs in three phases: planning, construction, and operation and maintenance. During the planning phase, local jurisdictions identify management practices that they anticipate would address the pollutant control plan set by the regional board. Because the local jurisdictions have varying characteristics, including land use and geographical features, each typically determines its own best means of compliance. During the construction phase, local jurisdictions implement their project plans, which can require significant amounts of capital to complete. Finally, during the operation and maintenance phase, local jurisdictions must conduct ongoing activities to ensure that their projects work as intended. One important component of the operation and maintenance phase is monitoring the storm water to ensure that the pollutants have been reduced. Local jurisdictions monitor pollutant levels by testing water samples. Local jurisdictions then provide those monitoring data to the regional board as evidence of their progress towards achieving pollutant limits.
The Los Angeles park project described earlier is a type of low impact development, an approach that can be more cost‑effective than traditional storm water treatment. The traditional system of pipes, filters, and retention basins for controlling water flow relies heavily on infrastructure. Low impact development focuses on using natural drainage features to manage storm water runoff as close to the source as possible and designing the landscaping to capture and filter storm water to reduce the volume of runoff from the site. For example, landscaping along streets and buildings can be designed to capture storm water that is then naturally filtered by plants and the soil. The advantage of low impact development is that it minimizes reliance on infrastructure by reducing the volume of runoff that needs to be processed. Under this scenario, less infrastructure needs to be installed for new developments and less wear and tear on existing infrastructure occurs, decreasing maintenance costs for upkeep.
The three regions we reviewed are encouraging the use of low impact development in various ways. Permits from all three regions require some degree of low impact development. In the San Francisco Bay Area, each permit holder is required to have a plan for incorporating low impact development into its storm drain infrastructure, including how the overall infrastructure will transition from the traditional to a more sustainable method over the long term. In the Central Valley, permit holders must require that high‑priority projects assess the possibility of integrating low impact development approaches, and applicable staff at the local jurisdiction must receive training that addresses low impact development. The Los Angeles permit requires that new development and redevelopment follow low impact development design principles and that permit holders involved in watershed management programs have or adopt low impact development ordinances and incorporate low impact development into their practices. The city of Los Angeles has also implemented a Green Streets program to add low impact elements to existing streets, and four such projects have received state grant funding. This technique has the potential to be a best practice that may help lower local jurisdictions’ costs of mitigating pollutants.
Jurisdictions can also mitigate costs by implementing projects collaboratively. The Los Angeles regional board has encouraged local jurisdictions to form groups based on their watershed—defined as a geographic area that discharges to a common water body, such as a lake or river—and most have done so. In addition, several local jurisdictions in the Los Angeles region are members of a joint powers authority that shares information and identifies common needs and issues for water management across boundaries. The San Francisco Bay region previously organized its permit by county; although that structure has since changed, local jurisdictions still cooperate within each county and through a Bay Area‑wide organization known as the Bay Area Stormwater Management Agencies Association. The organization’s objective is to share information among members and develop cost‑effective collaborative programs. Local jurisdictions have also collaborated in the Central Valley region. For example, the city of Sacramento and Sacramento County collaborate with other cities in their geographic area, such as the cities of Elk Grove and Galt, on monitoring, pollution reduction, and public outreach. These cooperative efforts are a best practice, as they can help reduce the cost of storm water management by spreading the cost of planning and monitoring across multiple municipalities and by identifying more cost‑effective projects.
1 We use the term maximum pollutant levels in this report as a proxy for various terms that the State Water Board and regional boards use to refer to required and recommended levels of pollutants that may be present in water bodies without interfering with the use of water. Such terms include water quality standards, water quality objectives, and water quality criteri. Go back to text
2 As discussed in the Scope and Methodology, our audit addressed Phase 1 storm water permits issued by three regional boards. Phase 1 permits are issued to local jurisdictions with a population of 100,000 or more. The State Water Board is also responsible for regulating storm water permits of smaller municipalities and nontraditional operations such as military bases, which were not included in the scope of this audit. Go back to text