Inventory of Significant Potential Sources of Contamination


A Source Water Protection Area Inventory consists of regulated and unregulated potential sources of contamination and associated contaminants of concern identified within the source water protection area or any known existing contamination in the area. The contaminants of concern include those raw water contaminants regulated under the Safe Drinking Water Act (SDWA) (those contaminants with a maximum contaminant level or "MCL"), contaminants regulated under the Surface Water Treatment Rule (SWTR), and the microorganism Cryptosporidium. The SWTR is designed to minimize risks from only a subset of microbial contaminants (Giardia, Legionella, and viruses). In addition, states may include those contaminants that are not federally regulated under the SDWA, but which the state has determined may present a threat to public health. The state does test for some unregulated organic chemicals and these are included in the list of contaminants of concern.

The U.S. EPA defines a Significant Potential Source of Contamination as any facility or activity that stores, uses, or produces, as a product or by-product, the contaminants of concern and has a sufficient likelihood of releasing such contaminants to the environment. The release would be at levels that could contribute significantly to the concentration of these contaminants in the source water of public water supplies. DEQ has developed a list of significant potential sources of contamination for ground water and surface water and ranked the potential sources into high, medium, and low risk categories based on sources of public water supply contamination in the past and experience of the staff. This is in essence a vulnerability analysis. Examples of significant potential sources of contamination include, but are not limited to, industrial facilities, underground storage tanks, auto repair shops, oil and gas activity, dry cleaners, abandoned water wells, and agriculture. Locations of significant potential sources of contamination within each source water protection area will be determined by field surveys and available databases.

Potential for Contamination by Significant Potential Sources of Contamination

Potential contamination sources are facilities that use, produce, or store contaminants of concern (those regulated under the Safe Drinking Water Act) which, if improperly managed, could find their way into a source of public drinking water. It is important to understand that a release may never occur provided they are using best management practices. Many are regulated at the federal level, state level, or both to reduce the risk of a release. There are a number of methods that water systems can use to work cooperatively with such facilities. These often involve educational visits and inspections of stored materials. Many owners of such facilities may not even be aware that they are located near a public water supply well or intake.


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