Hannibal has levels of Disinfection Byproducts above drinking water standards.

Este informe contiene información muy importante sorbe su agua potable. Tradúzcalo o hable con alguien que lo entienda bien.

The sampling and testing that resulted in the violation occurred during the 12 month period ending on September 30, 2015, and test results and the notice of violation were received on November 23, 2015.  This violation occurred before the installations of the new Ultraviolet (UV) Light and Chloramine Disinfection Systems at the Water Treatment Plant, which were completed in October of 2015 and should prevent future Disinfection by Products violations.

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

We routinely monitor for the presence of drinking water contaminants.  Testing results collected during the twelve (12) month period ending September 30, 2015 show that our system exceeded the standard or maximum contaminant level (MCL).  See table below.

Analyte Period End Date

Running Annual

Average (RAA)

RAA Unit of Measure


TTHM 9/30/15 96.9 ug/L 80 ug/L

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

What does this mean?
Disinfection Byproducts (DBPs) are formed when chlorine combines with naturally occurring organic matter in water.  Disinfection is necessary to inactivate harmful microbes, such as bacteria and viruses, which may be present in untreated water.  Regulated DBPs consist of Total Trihalomethanes (TTHMs) and Haloacetic Acids (HAAs).  The MCL is based on long-term exposure of drinking two (2) liters of water every day for seventy (70) years.  Some people who drink water containing THMs in excess of the MCL over many years may experience problems with their liver, kidneys or central nervous system, and may have an increased risk of getting cancer.

1 ug/L is equal to 1 part per billion (ppb).  One ppb is roughly equivalent to a teaspoon of a material in an Olympic size swimming pool, or one drop of ink in a canal lock full of water, or one second per 32 years.

What is being done?
Currently at the Water Treatment Plant construction is underway to improve the quality of the drinking water.  In October the UV and Chloramine Disinfection Systems were completed.  These improvements should reduce the Disinfection by Products within the drinking water and get them within the acceptable standards.  Other upgrades to the treatment plant are occurring as well and include a new carbon feed system and contact chamber, by pass piping to allow for certain treatment basins to be out of service, and various electrical and control system upgrades.  The project should be completed sometime in the spring of 2016.

Some may be asking why the public is being notified several months after the tests were completed.  Test results and the notice of violation were received in Hannibal on November 23, 2015.  And there was no acute danger with the Hannibal drinking water.

For more information and/or questions regarding this matter, please contact Heath N. Hall at (573) 221-8050 ext. 6037 or Herman McClain at (573) 221-0341.  Additionally you may contact the Missouri Department of Natural Resources’ Northeast Regional Office at (660) 385-8000 or Public Drinking Water Branch at (573) 751-5331.

Please share this information with all the other people who drink Hannibal’s water, especially those who may not have received this notice directly (for example, people in apartments, nursing homes, schools, and businesses).

This notice was sent to you by Hannibal
State Water System ID#:  MO2010344
December 2015


All HBPW customers will receive this notice with their December bill.  To download a printable copy of this notice, please click HERE