A pair of sample sites in Bristol reportedly showed levels of trihalomethane that could exceed federal regulations based on tests performed between April and August.
Bristol County Water Authority Executive Director Pamela Marchand said the two sites at the southern end of the system tested at roughly 90 and 100 parts per billion.
Ms. Marchand said new EPA regulations, which are enforced through the Rhode Island Department of Health, require that each sample site maintain an annual average — an average of the four most recent quarterly tests — of no more than 80 parts per billion.
Results from the latest sample tests are not available, and the state has not issued any violations against the BCWA.
Ms. Marchand said the regulations are a change from past practice because THM levels were formerly averaged from across the water district versus now, where they are tied to an individual sample site.
That means a low score in one Bristol County community won’t offset a higher number in another area.
Ms. Marchand said Barrington is likely to have lower THM samples than Bristol because Bristol County water enters the system from Providence on Nayatt Road.
THM forms through a mixture of chlorine and organic compounds found in water. The longer these two elements mix, the higher level of THM.
So Barrington customers, at the north of the system, consume Providence water earlier than those in Warren or Bristol. The water also has less time with chlorine, which is added from May-September to maintain measureable levels as dictated by Environmental Protection Agency guidelines.