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UCMR - Unregulated Contaminant Monitoring Rule
Massachusetts Water Resources Authority


Research for New Regulations

The US Environmental Protection Agency (EPA) periodically requires water systems across the country to conduct monitoring for substances that may be present in drinking water to help understand their national occurrence as part of the process of deciding whether to regulate them.  Under the Safe Drinking Water Act Amendments, EPA is required once every five years to develop a list of up to 30 new contaminants that must be monitored by public water systems. 

MWRA collected samples during 2013 at locations throughout our service area.  Additional sampling will occur in 2014 and 2015.  Even with the extremely sensitive test methods used capable of detecting some substances at parts per trillion levels, we expected to find very few of the substances that we were required to test for due to MWRA’s highly protected watershed and reservoirs. Only 4 of the 21 tested for in 2013 were detected, and all were at extremely low levels.    

Go to UCMR Main Page

Here is the complete list of 21 substances:

1,2,3-trichloropropane  bromomethane 
total chromium
hexavalent chromium
perfluorooctanesulfonic acid
perfluorooctanoic acid
perfluorobutanesulfonic acid
perfluorohexanesulfonic acid
perfluoroheptanoic acid
perfluorononanoic acid

More information on these substances and UCMR3 can be found on the US EPA Website.

We tested for these 21 substances in 2013, and these four were detected.  All other contaminants listed in the UCMR3 were not detected. 

Measurement Units
Total Chromium
parts per billion (ppb)

EPA already regulates total chromium with a Maximum Contaminant Level (MCL) of 100 ppb and a Maximum Contaminant Level Goal of 0.  It is found at low levels in most water as it is an abundant element in the Earth’s crust.  MWRA regularly tests for it and does not detect it with the normally required detection limit of 1 ppb.  Total chromium was included in the UCMR3 testing with a more sensitive detection level.  Results for total chromium were all below the normal detection limit, and far below the MCL of 100 ppb.   


Measurement Units
Hexavalent Chromium 
parts per billion (ppb)

Hexavalent chromium is one form of chromium and is not currently regulated by EPA, Massachusetts, or any other state.  It is commonly found in the environment, from both natural and manmade sources.  California has proposed a draft MCL of 10 ppb, and a finalized standard is expected in 2014.  MWRA levels are well below this standard.  Hexavalent chromium is noteworthy as the contaminant made famous in the movie Erin Brockovich starring Julia Roberts. 


Measurement Units
parts per billion (ppb)

Chlorate is a byproduct of disinfection with chlorine, and is commonly found in most waters in the US that use chlorine.  EPA and MA do regulate a number of disinfection by-products, and MWRA is well below those standards, but chlorate is not regulated at this time.  The World Health Organization has a provisional guideline value of 700 ppb, Health Canada has a guideline value of 1,000 ppb, and several years ago California proposed a standard (which was never finalized) of 500 ppb. EPA has not set a standard but has a provisional safe daily reference dose of 0.210 mg/l (210 ppb) for lifetime exposure.  MWRA levels are below all of these proposed or finalized standards.  


Measurement Units
parts per million (ppm)

Strontium is a metal that is common in nature, and small amounts are found in air, dust, soil, foods, and drinking water, though it is more commonly found at higher levels in ground water.   EPA has developed a non-regulatory lifetime health advisory of 4 ppm for strontium levels in drinking water.  MWRA levels are well below this health advisory.   


How will this data be used?

MWRA will continue to test for these substances under the UCMR3 during 2014 and 2015. Results will be reported in the Annual Water Quality Report.    
EPA will collect and analyze data for all three years and from systems all across the country to develop an understanding of the occurrence, level and distribution of these substances in drinking water.  That data, along with information on potential health effects and water treatment effectiveness will be used by EPA to determine if any new regulations are needed. 


Posted May 28, 2014

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