Special Topics in Environmental Management

Unregulated Contaminant Drinking Water Monitoring Underway

Approximately 6,000 selected drinking water suppliers nationwide are in the process of complying with the 2012 “Revisions to the Unregulated Contaminant Monitoring Rule (UCMR 3) for Public Water Systems,” under the Safe Drinking Water Act (SDWA) amendments of 1996. The contaminants named in the lists are not already regulated by the National Primary Drinking Water Regulations; however they are known or anticipated to occur in public drinking water systems.

UCMR 3 is the fourth cycle of monitoring, following UCMR 2 from 2007–2011, UMCR 1 from 2001–2005, and the first from 1988–1997, which was implemented at the state level. On the one hand, it is good to know our drinking water is being tested fairly routinely, and on the other hand, it is also a heads-up for facilities that use or produce any of the listed unregulated contaminants in their processes, as the data collected help determine if new regulations may be imposed based on danger to public health.

Since UCMR 2 in 2007, changes have been made to UCMR 3 to “improve the rule design,” including new contaminants and analytical methods. Other changes include:

  • Inclusion of public water systems (PWSs) that purchase all of their water,
  • Clarification of the terms of representative groundwater sampling, and
  • Updated reporting elements (including adding one for zip codes for customers served by PWSs).

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The contaminants are divided into three groups:

  • List 1 contaminants include volatile organic compounds (VOCs), synthetic organic compounds, metals, chromium-6, oxyhalide anion, and perfluorinated compounds;
  • List 2 contaminants include hormones; and
  • List 3 contaminants include two viruses—enterovirus and norovirus.

For each contaminant group, the EPA has set requirements for different size PWSs, depending on the number of people served by each system:

List 1 Assessment Monitoring: The following PWSs will monitor for 21 chemicals during a 12-month period from 2013–2015.

  • All PWSs serving more than 10,000 people (i.e., large systems), and
  • 800 representative PWSs serving 10,000 or fewer people (i.e., small systems).

List 2 Screening Survey: The following PWSs will monitor for seven chemicals during a 12-month period from 2013–2015.

  • All PWSs serving more than 100,000 people,
  • A representative sample of 320 large PWSs, and
  • A representative sample of 480 small PWSs.

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List 3 Pre-Screen Testing: The following PWSs will monitor for enterovirus and norovirus and related pathogen indicators (i.e., total coliforms, E. coli, bacteriophage, Enterococci, and aerobic spores) during a 12-month period from 2013–2015. The virus monitoring will take place in sensitive hydrogeological areas (e.g., karst or fractured bedrock).

  • A representative sample of 800  nondisinfecting  groundwater systems serving 1,000 or fewer retail customers, including community water systems (CWSs), non-transient non-community water systems (NTNCWSs) and transient systems are required to participate in Pre-Screen Testing.

Samples for all contaminants will be collected at distribution system entry points and List 1 Assessment Monitoring samples for chromium, chromium-6, cobalt, molybdenum, strontium, vanadium, and chlorate will be collected in the distribution system, as well. The time frame for required monitoring is
one consecutive 12-month period during January 2013–December 2015 (Monitoring can span more than 1 calendar year, as long as it is conducted during a consecutive 12-month period.).

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