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Unregulated Contaminant Monitoring Rule (UCMR)

  Water Info / What's in My Water? / Unregulated Contaminant Monitoring Rule (UCMR)

Egyptians drinking water

 

What is the UCMR?

Under the 1996 amendments to the federal Safe Drinking Water Act, the U.S. Environmental Protection Agency is required once every five years to issue a new list of up to 30 unregulated contaminants for which public water systems must monitor. The intent of this rule is to provide baseline occurrence data that the EPA can combine with toxicological research to make decisions about potential future drinking water regulations.

The most recent UCMR, the Fourth Unregulated Contaminant Monitoring Rule (UCMR4), was signed by former EPA Administrator Gina McCarthy on Dec. 20, 2016. The EPA, the states, laboratories and public water systems participate in the testing for UCMR4 in various ways. The testing occurs between January 2018 and December 2020.

The contaminants monitored under UCMR4 include:

 

Ten Cyanotoxin Chemical Contaminants Two Metals Three Brominated Haloacetic Acid (HAA) Groups

 

Eight Pesticides and One Pesticide Manufacturing Byproduct
  • alpha-hexachlorocyclohexane
  • chlorpyrifos
  • dimethipin
  • ethoprop
  • oxyfluorfen
  • profenofos
  • tebuconazole
  • total permethrin (cis- & trans-)
  • tribufos
Three Alcohols
  • 1-butanoll
  • 2-methoxyethanol
  • 2-propen-1-ol
Three Other Semivolatile Chemicals
  • butylated hydroxyanisole
  • o-toluidine
  • quinoline

It is likely that your water provider participates in UCMR testing in some capacity. All public water systems serving more than 10,000 people participate in the testing. And 1,600 representative small PWSs serving 10,000 or fewer people will participate in at least a portion of the UCMR 4 testing. The testing occurs between January 2018 and December 2020. You can contact your local water provider to ask about its participation in UCMR testing.

The test results are used to help determine whether or not certain contaminants are found in drinking water, at what levels they are found, and in which parts of the country.

Depending on how prevalent the contaminants are and at what levels they are found, EPA may conduct further research to determine whether or not to begin regulating some or all of them.

In many cases, utilities will be testing for these contaminants at very low levels. That does not mean those contaminants have been determined to be harmful at those levels. The EPA sets these testing levels based on the capabilities of current analytical methods and the agency's need to identify reference concentrations, so that they can offer context when they are making health-based regulatory decisions.