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TOC Violation 8-2021


Treatment Technique Not Met for CITY OF OSAWATOMIE

Our water system recently violated a drinking water standard.  Although this is not an emergency, as our customers you have a right to know what happened, what you should do, and what we are doing to correct this situation.

Water systems with surface water and / or groundwater under the influence of surface water treatment plants are required by federal rule to monitor the water every month for Total Organic Carbon (TOC), which is a disinfection by-product precursor.  Compliance is determined each calendar quarter by a 12 month running annual average (RAA).  For TOC, we are required to meet a removal efficiency that is dependent on the source TOC as well as the alkalinity.

You do not need to use an alternative (e.g., bottled) water supply.  However, if you have specific health concerns, consult your doctor.

What does this mean?

This is not an immediate risk. If it had been, you would have been notified immediately.  TOC has no health effects.  However, TOC provides a medium for the formation of disinfection by-products such as Trihalomethanes (TTHM) and Haloacetic Acids (HAA).  Drinking water containing HAA or TTHM in excess of the Maximum Contaminant Level (MCL) may lead to adverse health effects, liver or kidney problems, and may lead to an increased risk of getting cancer. 

What happened? What is being done?

A running annual average means that we must meet a certain requirement over the course of 12 months. The violation in question is Total Organic Carbon removal. We are required to be at an annual average ratio of 1 or greater, we are currently at 0.97. However, this is not representative of your current water- the last time we failed an individual test was January of this year.

           Our water is currently very good with regard to TOC removal, last month was a 62% removal, where we were only required to remove 40%. Last month’s removal ratio was 1.5, well above the KDHE required minimum of 1.0. Source water quality effects our TOC removal ability. We have made modifications to our polymer dosing and sampling techniques to try to avoid this problem going forward

           I want to once more emphasize that your current water quality is within KDHE parameters.

We anticipate resolving the problem by the next quarter.  Due to the running annual average, it may take 1-2 quarters to get the average back up over 1.00.

For more information, please contact:   



Or by Mail:  509 5TH ST, PO BOX 37, OSAWATOMIE, KS  66064

Please share this information with all the other people who drink this water, especially those who may not have received this notice directly (for example, people in apartments, nursing homes, schools, and businesses). You can do this by posting this notice in a public place or distributing copies by hand or mail.

This notice is being sent to you by CITY OF OSAWATOMIE.

Federal ID #:  KS2012105