Watertown will now require commercial developers to put solar panels on new buildings, becoming the first town in New England to do so.
The town council unanimously approved a zoning ordinance requiring new commercial construction, as well as renovations of existing buildings that are more than 10,000 square feet, to have solar collectors.
Cambridge is considering a similar solar requirement, as both communities have been undergoing construction booms.
Vincent Piccirilli, vice president of the town council, said the plan has been in the works for about a year-and-a-half.
"It grew out of concern with all the development in Watertown," he said, "that we really should be doing more to require developers to do something to help the environment, particular with solar energy generation."