Many customers have reported discolored water over the past several weeks the root cause of which is a change in source water chemistry. All of our water comes from groundwater wells. The slight change in the ground water has made minerals that contain manganese near the wells more soluble. Two of the treatment processes that we currently use to meet Safe Drinking Water Act regulations, chlorination and corrosion control, severely reduce the solubility of manganese which causes it to form a powder like coating on virtually all interior piping surfaces including water mains, service lines and home plumbing. Discolored water occurs when this coating is disturbed and the powder becomes suspended in the water turning the water brown and sometimes black. A disturbance, such as a water main break, can cause issues system wide or something as simple as filling the bathtub can loosen the deposits in your own service line.
Recently the occurrence of discolored water appears to be more frequent, more widespread and longer in duration than in previous years. This is due to several factors including the time of year, recent water main breaks, authorized and unauthorized use of fire hydrants and flushing inefficiencies. Each year we flush hydrants in the spring and fall to remove as much of the manganese deposits from the water mains as possible. Despite our best efforts and the adoption of more efficient flushing routines, some deposits remain in the system. The highest amount of sediment accumulation occurs just prior to the fall flushing round because more water is pumped during the summer than during the winter and deposits tend to be thicker as a result. Recently there were two water main breaks which caused widespread issues due to the extremely high flows generated. There were also several authorized and, we suspect on at least one occasion, unauthorized use of fire hydrants that caused discolored water for large areas of Town. These events occurred at a time when the deposits in the mains are at their greatest.
Many customers have asked about the health effects of the discolored water. Manganese is a naturally occurring element and an essential nutrient. As far as drinking water is concerned, manganese is considered a secondary contaminant which means recommended levels have been set by the United States Environmental Protection Agency (EPA) for aesthetic reasons to prevent staining and discoloration. Based on information provided by EPA, there are no known links between manganese in drinking water and cancer for both humans and animals. There is little data connecting manganese in drinking water to other health effects; however EPA has set some guidelines to guard against potential links. For this reason we do not recommend using water for drinking, cooking or making formula if the water is discolored.
There are two possible solutions for this type of contamination. We are in the final stage of installing the first and less expensive option, a sequestrant system, which will add a polyphosphate/orthophosphate blend to the water that will bind the manganese in a soluble state to prevent the chlorination and corrosion control processes from forcing it out of solution. The system will be online once the Massachusetts Department of Environmental Protection (DEP) conducts their final inspection which will hopefully be completed in the next few weeks. The effect of the sequestrant will be two fold. The rate of coating formation will decrease thereby reducing the frequency and severity of discolored water over time. As a result of keeping the manganese in solution, concentrations in clear water will approach levels found in the source water. We plan to regularly test manganese and phosphate levels throughout the distribution system and will notify you if the manganese concentration in clear water reaches a point of concern.
The second solution is to build a water treatment plant that will remove manganese from the water. Building a treatment plant is a multi-million dollar project that would be completed in stages over several fiscal years. A project such as this would address a multitude of water quality concerns including chlorination alternatives as well as compliance with future drinking water regulations. This winter we plan to conduct a study that will evaluate possible treatment methods, review site requirements and develop cost estimates for design, construction and operation. Subsequent stages, including design and construction of the plant, would be proposed at a later date based on sequestrant effectiveness, changes to drinking water regulations or new health effects data.
Please visit our website, www.topsfieldpublicworks.org, for information about the sequestrant system and its status. Please contact the Water Department at (978) 887-1517 if your water is discolored and it doesn’t clear after running the cold water; it may be time to have your water service flushed. As residents of Topsfield and public water customers, we are confronted with the same water quality issues as our customers. In the coming years, we will attempt to balance the need for investment in our water infrastructure with the limited supply of funding and appreciate your support as well as your patience. Thank you.
Sincerely,
The Topsfield Board of Water Commissioners
Philip Knowles, Chairman
Richard Stone, Clerk
Elizabeth Cullinan, Member
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