The state is now testing the new formula in four water districts — Amherst, Danvers-Middleton, Dedham-Westwood, and Shrewsbury — to understand impacts of the formula to help better draft final rules.
State officials say they envision more communities will become like Franklin, which has decreased town water use by about 500,000 gallons a day, to about 2.6 million gallons. Jeff Nutting, Franklin’s town administrator, said the community accomplished that, in part, by fixing leaks, restricting residential lawn watering to one day a week, getting rid of sidewalks on one side of some subdivision streets to allow water to seep back into the earth, and creating rain gardens.
The downside in Franklin was that water rates went up, Nutting said. That is because there are fixed costs in sanitizing and delivering water, so if water use goes down, the per-gallon cost to cover those fixed costs must go up. But, he added, conservation efforts have helped cut demand and cost.
“For the first time, DEP has the science — and plans to use it — to connect water allocation to stream flow,’’ said Julia Blatt of the Massachusetts Rivers Alliance, a coalition of state river and environmental groups. But “as with any large, complicated new policy, the devil is in the details,” she said.