TEWKSBURY — Postcards with the link to the latest town water consumer confidence report were delivered recently to residents. Provided on a quarterly basis, the report details information for the community about the town’s water purification and distribution system.
Of note in this report is the statement by the water department that the town is completely within compliance for 2022 with respect to the TTHMs. Tewksbury had exceeded the Maximum Contaminant Level for Total Trihalomethanes (TTHMs) in 2021 due to high levels of organic compounds in the Merrimack River, the town’s drinking water source.
In an interview in 2021, Assistant Utilities Director Scott Brinch said, “The Total Organic Compounds in the Merrimack are at the highest level anyone can remember,” referring to last summer’s heatwaves, heavy rain events, and large algae blooms.
Brinch explained that TTHMs are formed when chlorine, which is added to drinking water to combat bacteria, combines with organic material in water over time.
Since TTHMs are sampled quarterly at several locations throughout the system, Tewksbury’s level in August of 2021 exceeded allowable levels. Compliance with EPA levels is determined by calculating a rolling annual average and as such, it took several quarters for Tewksbury’s numbers to meet acceptable levels, despite the immediate response of the water department.
Concerns about elevated levels of trihalomethanes stem from research that show that TTHMs, at high concentrations over many, many years, could potentially have negative reproductive outcomes. TTHMs are produced when bleach is added to water as part of the disinfection process. Four sites in Tewksbury are monitored on a quarterly basis and the treatment process is adjusted to minimize the production of TTHMs.
The report states that “as part of the response to getting our TTHMs back in compliance, the town worked with AECOM, a consultant that has expertise in drinking water treatment. A number of improvements were made, including more efficient chlorine dosing, more frequent sampling, filter basin cleaning, and increased usage of our aeration blowers which reduce organic compounds in the water.”
Tewksbury samples 13 sites on a weekly basis to test for bacteria and free chlorine. Free chlorine is always detected at all sample sites, which indicates the town’s water is very stable. Residual chlorine gives additional protection against harmful bacteria according to the report.
The EPA and Massachusetts Department of Environmental Protection require specific language to be included in water reports. However, according to the Tewksbury water report, much of the required language may not be relevant to the Tewksbury Water System in particular.
The water department recommends flushing hot water tanks once or twice each year to reduce sediment to keep household water cleaner and extend the life of a homeowner’s hot water tank.
The town retains a consultant to regularly review the town’s PFAS level to be sure that levels are safe. PFAS are a class of “forever chemicals” that are a by product of non-stick coatings on cookware, fire fighting foam, pesticides, shampoos, and other products that make their way to drinking water sources.
Tewksbury’s PFAS level is well below the EPA’s Maximum Contaminant Level, according to the report. The report did indicate that the water department missed a confirmatory PFAS reading in Q2 2021. The department will now undergo quarterly PFAS testing but at no time were regular samples out of compliance for safe PFAS levels in drinking water according to the report.
Director Brinch urges any resident with questions or concerns about Tewksbury’s drinking water to contact him at 978-640-4440. The report may be found on the town website at www.tewksbury-ma.gov/CCR2021.