Unregulated Contaminant Monitoring Rule (UCMR)
Egyptians drinking water
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 will participate in the testing for UCMR4 in various ways. The testing will occur between January 2018 and December 2020.
The contaminants that will be monitored under UCMR4 include:


Ten Cyanotoxin Chemical Contaminants
  • total microcystin
  • microcystin-LA
  • microcystin-LF
  • microcystin-LR
  • microcystin-LY
  • microcystin-RR
  • microcystin-YR
  • nodularin
  • anatoxin-a
  • cylindrospermopsin
Two Metals
  • germanium
  • manganese
Three Brominated Haloacetic Acid (HAA) Groups
  • HAA5
  • HAA6Br
  • HAA9


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, 800 representative PWSs serving 10,000 or fewer people, and 800 representative PWSs serving 1,000 or fewer people will participate in the UCMR4 testing. The testing will occur 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.

The most recent round of testing ended December 2015. Depending on how prevalent the contaminants were and at what levels they were found, EPA may conduct further research to determine whether or not to begin regulating some or all of them.

The next round of testing will begin in January 2018.