Disinfectant Residual Water Violation - Notice Distributed 7/2/18

Plainville Public Water System Did Not Meet Treatment Requirements

Our water system recently violated a drinking water standard.  Although this situation does not require that you take immediate action, as our customers, you have a right to know what happened, what you should do, and what we are doing to correct this situation.

Disinfectant Residual - We routinely monitor for disinfectant residual in the distribution system.  This measurement tells us whether we are effectively disinfecting the water supply.

Single Exceedance - On June 5, 2018, disinfectant levels dropped below 0.2 milligrams per liter for 8 hours.  The standard is that levels may not drop below 0.2 mg/l for more than 4 hours.


  • You do not need to boil your water or take other corrective actions.  However, if you have specific health concerns, consult your doctor.                                                               
  • People with severely comprised immune systems, infants, and some elderly may be at an increased risk.  These people should seek advice about drinking water from their health care providers.  General guidelines on ways to lessen the risk of infection by microbes are available from EPA's Safe Drinking Hotline at 800-426-4791.


This situation does not require that you take immediate action.  if it had, you would have been notified immediately.  Tests taken during this same time period did not indicate the presence of bacteria in the water.

Inadequately treated water may contain disease-causing organisms.  These organisms include bacteria, viruses, and parasites which can cause symptoms such as nausea, cramps, diarrhea, and associated headaches.

These symptoms, however, are not caused only by organisms in drinking water, but also by other factors.  If you experience any of these symptoms and they persist, you may want to seek medical advice.


On June 5, 2018, disinfectant residual fell below the required .20 milligrams per liter for more than 4 hours.

Over the past several months, we have made adjustments to lower the chlorine residual to reduce the levels of the disinfection by-products (TTHM/HAA5).  Although these adjustments have helped to lower levels of TTHM and HAA5, they have also resulted in the violation of a treatment requirement.


We have adjusted disinfectant levels and are maintaining chlorine residuals above 0.20 mg/l.  Bacteria samples were taken on June 6, 2018 and were absent of bacteria.

For more information, please contact Dennis Morton at 508-695-6871.

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 Plainville Water Department, PWS ID#:42380000.  Date distributed: 7/2/2018.

Please see attachment for additional information.