Starting next month, Portland will require that all new single-family homes and duplexes be built with fire sprinkler systems.

The City Council last week voted Aug. 16 to update the city’s fire safety code and became the third Maine community, after Westbrook and Rockland, to adopt the requirement, according to the National Fire Sprinkler Association.

The new standard takes effect Sept. 15 and means that all residential construction is now covered, according to Ben Wallace, Portland’s fire safety officer. Multi-family residential construction already was required to include sprinklers.

The cost of a sprinkler system could add 1 or 2 percent to the cost of a typical single-family home – one builder estimated as much as $4,500 – but also would reduce the costs of homeowner’s insurance, Wallace said.