Report 98112 Summary - December 1998

California's Drinking Water: State and Local Agencies Need to Provide Leadership to Address Contamination of Groundwater by Gasoline Components and Additives


Although the State of California has ample evidence that gasoline leaking from underground storage tanks is jeopardizing the safety of our drinking-water supplies, it has not acted quickly and decisively to address this potential health hazard. The scientific community and the public are particularly concerned about leaking storage tanks contaminating numerous groundwater sites and some drinking-water wells with methyl tertiary-butyl ether (MTBE), a gasoline additive that reduces air pollution from automobile exhaust, but which the federal government has classified as a possible cancer-causing agent.

State legislation directs various state and local agencies to oversee the safety of California's drinking water, including the Department of Health Services (Health Services), the State Water Resources Control Board (state board), the California Environmental Protection Agency (California EPA), and nine Regional Water Quality Control Boards (regional boards). As early as 1990, Health Services' officials became aware that MTBE was contaminating drinking-water wells within California; however, Health Services did not establish regulations to test for MTBE in drinking water until 1997, nor did it adopt interim emergency regulations, even though it has the authority to do so. The state board also shares responsibility for not providing leadership to the regional boards and local agencies responsible for alleviating groundwater contamination because it has not yet issued specific guidelines or standardized procedures for cleaning up MTBE. Thus, MTBE levels at some contaminated groundwater sites remain high, posing potential threats to nearby drinking-water wells.

Moreover, the State's process for regulating the safety of its citizens' water, and especially for ensuring that gasoline does not contaminate drinking-water sources, has multiple shortcomings. The State has been inconsistent in its efforts to identify and clean up leaking underground storage tanks, and the California EPA's approach for overseeing the local agencies responsible for issuing permits to storage tank operators and for monitoring the tanks may not assure that the agencies catch all leaks and deficiencies. Health Services' procedures for obtaining sample analyses from public water systems also have flaws. Health Services needs to improve its procedures to ensure that public water systems submit laboratory results promptly so that agencies can identify and alleviate contamination quickly.

To further compound the problems surrounding MTBE contamination, Health Services and the state and regional boards are not making certain that public water system operators, storage tank owners or operators, and regulatory agencies responsible for detecting and cleaning up chemical contamination are doing their jobs. Not only does the State regulate underground storage tanks ineffectively, it has failed in some instances to aggressively enforce the State's Safe Drinking Water Act and the laws governing underground storage tanks. Specifically, Health Services, the regional boards, and local agencies have not adequately enforced laws that require prompt follow-up monitoring for chemical findings and contaminated sites, notified the public about chemicals found in drinking water, and managed the complete cleanup of chemical contamination of groundwater. P> Some regulatory problems arise from poor communication among various state and local agencies. However, a geographical information system (GIS)-the State's proposed solution for assessing contamination risks to drinking-water sources, as well as for relaying information about these risks to responsible agencies-also requires improvement. Currently, both Health Services and the state board are working on GIS projects to map potential sources of drinking-water contamination, and this duplication of effort could be unnecessarily costly to the State. Health Services should serve as the lead developer for the GIS because it can use the system to evaluate risks to the State's approximately 16,000 drinking-water sources and thus accomplish the goals of the federally mandated Drinking Water Source Assessment and Protection Program. Finally, neither agency can effectively implement a GIS until the State significantly improves the databases containing information on the locations of possible contamination. RECOMMENDATIONS

To ensure that California's drinking water is safe from contamination by gasoline leaking from underground storage tanks, the California Environmental Protection Agency and the Health and Welfare Agency, which oversees Health Services, need to make certain that the state, regional, and local agencies listed below fulfill their designated responsibilities and improve their policies and procedures in the ways outlined.

The California Environmental Protection Agency needs to take the following steps to locate leaking underground storage tanks:

The Department of Health Services needs to do the following to manage threats to drinking water systems:

The State Water Resources Control Board should act on the following suggestions to help prevent further contamination of drinking-water wells:

Further, the regional boards and local oversight program agencies directly responsible for managing groundwater sites affected by gasoline should take the following actions:


The Department of Health Services generally agrees with the recommendations in our report, with the exception of our recommendation that it should no longer permit its staff to round off the numbers when determining whether a chemical exceeds the maximum contaminant level. Additionally, Health Services still believes that emergency regulations were not justified and that the approach it took to regulate MTBE was prudent. Finally, Health Services states that if it is to expand its role on the State's GIS projects, it will require a substantial increase in resources.

Similar to Health Services, the State Water Resources Control Board generally concurs with the recommendations in our report. However, the state board believes that it would be appropriate for it to complete the tasks for its existing GIS project, outlined in the 1997 legislation, before Health Services assumes the lead role for ensuring that a GIS provides the necessary information to protect drinking-water wells. Also, the state board indicates that it will work cooperatively with Health Services to ensure that it avoids duplication of efforts and that its efforts are complementary to those of Health Services.

Finally, the California Environmental Protection Agency supports the position taken by the state board. In addition, the California EPA provides some supplemental information about its Unified Program.