Evaluating Extremely Impaired Drinking Water Sources

Speaker:Stefan Cajina, P.E.
District Engineer, Central District
California Department of Health Services
Drinking Water ProgramAbstractThe primary goal of the California Department of Health Services, Drinking Water Program (CDHS) is to ensure that all Californians receive a reliable supply of safe drinking water. To this end, CDHS seeks to approve the use of only high-quality sources of drinking water. As populations increase, however, and domestic demands on the state's water resources grow, more water utilities are proposing to treat and distribute water from "extremely impaired" sources to their customers. CDHS may consider a drinking water source to be extremely impaired for various reasons, including high levels of contamination, a mixture of contaminants of health concern, proximity to known contaminating activities, or use of the source to intercept contaminants of health concern.The use of extremely impaired sources of drinking water may increase the health risk to the public, and should therefore be avoided when high-quality sources are available. In the past, some treatment projects involving extremely impaired sources have proved inadequate due to increasing contaminant levels or the appearance of unexpected contaminants. However, CDHS recognizes that many local water supplies need to be cleaned up, and that the resulting product water represents a significant resource that should not be wasted. In some situations, particularly when high-quality sources are overtaxed or unavailable, CDHS may consider the use of extremely impaired sources for domestic water supply. In such cases, the source water must be thoroughly and reliably treated to remove all contaminants of health concern. In order to approve such a project, CDHS must thoroughly evaluate the proposal and conclude that public health is adequately protected. In addition, the project must be acceptable to consumers. CDHS developed Policy Memorandum 97-005 – Policy Guidance for Direct Domestic Use of Extremely Impaired Sources, to guide staff in the evaluation of such proposals.The evaluation process as set forth in Policy 97-005 consists of 12 essential elements:
1. Source water assessment
2. Full characterization of the raw water quality
3. Evaluation of source protection program
4. Evaluation of monitoring and treatment
5. Evaluation of human health risks associated with failure of proposed treatment
6. Identification of alternatives to the use of the extremely impaired source and comparison of potential health risks
7. Completion of the California Environmental Quality Act (CEQA) review of the project
8. Submittal of a permit application
9. Public hearing
10. CDHS evaluation
11. Finding that project meets or does not meet CDHS requirements for approval
12.Issuance or denial of permitBy completing the Policy 97-005 evaluation process, water utilities, CDHS, and the public can make informed decisions regarding the use of extremely impaired sources. Any treatment project that is approved by CDHS for domestic water supply may be expected to protect public health for the life of the project.

Location: Kaprielian Hall (KAP) - rielian Hall 156

Audiences: Everyone Is Invited

Contact: Evangeline Reyes