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The UCMR is the mandated starting point for a process that prioritizes 30 unregulated drinking water contaminants, first for sampling and analysis, followed by further prioritization of five or more contaminants for regulatory consideration.
To undertake regulation of a contaminant, the EPA must first establish that each of the following is met:
1. The contaminant may have an adverse effect on the health of persons;
2. The contaminant is known to occur or there is a substantial likelihood the contaminant will occur in public water systems with a frequency and at levels of public health concern; and
3. In the sole judgment of the Administrator, regulation of the contaminant presents a meaningful opportunity for health risk reductions for persons served by public water systems.
The information necessary to make these determinations can only be provided by laboratories sanctioned by the EPA through the Laboratory Approval Program that assesses equipment, laboratory performance, and data reporting criteria specifically for the current UCMR 3. All UCMR 3 participating Public Water Systems (PWSs) are required to use only EPA-approved laboratories that must adhere to the quality assurance and quality control (QA/QC) procedures and criteria established in the rule and the methods.
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Reporting under the UCMR 3 is similar to reporting under UCMR 2 and laboratories providing sample analysis initially post their data to EPA’s Safe Drinking Water Accession and Review System (SDWARS) a web-based platform accessible through the agency’s Central Data Exchange. Following posting of the data, PWSs must then review and act on data within the SDWARS system.
In addition to the UCMR 3 requirements for PWSs, two other rules are integrated in the reporting requirements that may impact actions required under UCMR 3:
The Consumer Confidence Report (CCR) Rule that requires community water systems—those PWSs serving the same population year-round—to provide Consumer Confidence Reports, (also known as annual water quality reports or drinking water quality reports) to their customers. The reports are due to customers by July 1 of each year, and they summarize drinking water information such as sources, detected contaminants, and compliance and educational information.
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The Public Notification (PN) Rule, which was revised in 2000, provides the standard language and procedures for both agencies and PWSs to follow when notifying the public of a drinking water emergency, such as a boil water emergency, or for less critical events like when a test is missed. The EPA established three Tiers for how quickly PWSs must notify the public of drinking water violations:
Tier 1—Immediate Notice within 24 hours is for situations that pose immediate danger to human health from drinking the water,
Tier 2—Notice as soon as possible or within 30 days of the violation when a contaminant exceeds EPA/state standards but does not pose an immediate risk to human health, and
Tier 3—Annual Notice when a violation has occurred that does not have a direct impact on human health.
Once a laboratory submits a PWS’s drinking water analysis data to the SDWARS, PWSs are responsible for approving and submitting analytical results to the EPA using SDWARS. PWSs must act on their data within 60 days of the laboratory posting date or the EPA will consider the data approved by the PWS and available to the EPA for review and public release. Approved UCMR data is available via the National Contaminant Occurrence Database (NCOD) and the UCMR Occurrence Database.