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City of Bloomington Officials Report Decline in July 2016 Disinfectant Byproduct Levels

August 18, 2016

For more information please contact: Vic Kelson, City of Bloomington Utilities Director, 812.349.3650;

City of Bloomington Officials Report Decline in July 2016 Disinfectant Byproduct Levels

Bloomington, Ind. - The monthly disinfectant byproduct (DBP) test results for July have been released, and the levels are lower than in June of this year and well below July 2015 levels. In 2016 CBU began collecting DBP samples on a monthly basis and over the January-July 2016 period no individual samples have exceeded the maximum contaminant level (MCL).

The June 2016 findings showed the concentration of haloacetic acid (HAA5) levels at the eight locations tested ranged from 49 to 56 parts per billion (ppb) and the trihalomethanes (THM) levels were between 53.7 and 71.8 ppb.

The July 2016 findings revealed the concentration of HAA5 levels at the eight testing sites ranged from 38.7 to 46.8 ppb and the THM levels were between 52.6 and 64.9 ppb.

Results from both June and July are below 60 ppb for haloacetic acids and 80 ppb for trihalomethanes.

One year ago, the July 2015 samples showed ranges of 52-60 ppb for HAA5 and 84.3-95.5 ppb for THM. In 2015, DBP samples were collected once per quarter at 8 sampling locations. EPA regulations are based on annual average DBP concentrations, and samples collected by CBU have never violated the annual-average standard. Individual samples have occasionally exceeded the 60 ppb and 80 ppb level; in 2015, 15 individual samples exceeded 60 and 80 ppb over the January-July period (8 for THM and 7 for HAA5).

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"Going into the heat of the summer we were concerned about the potential for our DBP numbers to rise, as is customary for this time of year. We are happy to have numbers to report that are a decline from June, despite a hot July. Of course we will test water quality monthly while we continue to modify and improve our water treatment practices," said Mayor John Hamilton.

Disinfectant byproduct levels are generally higher during the summer and fall, and CBU staff have responded accordingly.

"Our optimization team has been monitoring the disinfection process in the Monroe plant, and we were able to reduce the chlorine feed rate in three steps over the June-July period," said CBU Director Vic Kelson. "The reduced chlorine contact tends to reduce DBP production while still achieving the disinfection required by the State of Indiana."

Monthly water testing was initiated in January of this year in an effort to better track water quality, specifically DPBs. Testing of CBU water is conducted by a private, independent laboratory. All water quality test results are available online at under 'Utilities."