Coliform bacteria found in Marthasville’s public water system led to an agreement earlier this month to flush the system with disinfectant, according to a Missouri Department of Natural Resources (DNR) representative.The city announced March 6 that it would voluntarily begin disinfecting its water supply system at the request of DNR.Joe Stoops, public drinking water unit supervisor at DNR’s St. Louis Regional Office, said that decision was made after water samples over the last 18 months have shown the presence of coliform bacteria.While the bacteria is mostly not harmful, it is used as an indicator of contamination where more harmful bacteria could be present, Stoops explained.“Conditions exist where other things can potentially grow, and as a corrective measure, (the city has) agreed to begin using chlorine to disinfect the system,” Stoops said.Water samples are also tested for E. coli bacteria, which could indicate more serious contamination. No recent samples have shown that bacteria to be present.According to online DNR records, water samples showed coliform contamination in October 2016, off and on throughout 2017, and as recently as the end of February 2018.When enough samples with those results happen so close together, it triggers a response from DNR, Stoops said. The first thing inspectors do is look for a clear source of contamination, but none was found.“Because no obvious cause was located and repaired, the next step was to begin with disinfection,” Stoops explained. “Chlorine disinfectant has a very long and very successful history of being effective as an additional protective layer for maintaining water quality and public health.”Residual chlorine levels will continue to be maintained in the water for the foreseeable future, Stoops said.Mayor David Lange said the city is doing what it needs to ensure high quality drinking water for its citizens, and did repair one point of damage that could have led to contamination.In the near future, the city plans to build a new well and water storage that will allow old infrastructure to be taken off-line, Lange said. Once that is done, the city plans to stop adding chlorine for a year.As long as the city has only one or no coliform positive samples for that 12 months, DNR will be satisfied, Lange said. He added that he would prefer the city not have to add chlorine.“We’re trying to look out for the safety of the citizens and put out the best product we can, water-wise. I’m probably the last person who likes the taste of chlorine in the water,” Lange said.Marthasville