Last Thursday, the Dedham-Westwood Water District released a drinking water notice revealing routine testing of the District's facilities had yielded an isolated positive E. coli result:
"We routinely monitor for the presence of drinking water contaminants to ensure the safety of the water supply. On July 12, 2017, our water system learned that a raw (untreated) water sample collected on July 11, 2017 at the White Lodge Water Treatment Plant tested positive for E. coli, which is a fecal indicator. Fecal indicators are used to detect ground water sources that may be susceptible to fecal contamination which may contain harmful viruses or bacteria. Raw water samples from all five of the wells treated at the Plant tested clean, but a sample collected of combined raw water tested positive. The White Lodge Water Treatment Plant was turned off once we learned of the sample result, and is presently turned off.
"The water delivered to your taps through the distribution system is disinfected with chlorine to kill viruses and bacteria, including E. coli. It is important to note that the treated water from the Plant and treated samples collected in the distribution system did NOT detect any fecal contaminants.
"Even though none of the chlorinated samples tested positive, our chlorine disinfection system at the White Lodge Water Treatment Plant has not been certified by the MassDEP as 4-log compliant for 99.99% virus inactivation. In accordance with the federal Ground Water Rule (GWR) requirements, we are notifying you of the situation and conducting additional sampling to evaluate the extent of potential fecal contamination and will take further actions as necessary."