CENTER HARBOR, N.H. – Residents in Center Harbor and Moultonborough are facing a decision on whether new boathouses are worth risking the spread of the insidious underwater plant milfoil.

Each community on Squam Lake will consider articles at town meetings to ban new boathouses. Others towns on the lake have imposed similar bans.

Supporters of the ban say boathouses harm the ecology and shoreline. Opponents say residents who pay high prices for waterfront property and luxurious boats should be able to build a structure to protect the boats.

State law says boathouses must be dug into the ground, which requires some dredging. Environmental experts say dredge areas backfill with silt, a prime breeding ground for milfoil.

Official have contained milfoil as best they could, but it spreads and grows very quickly, and if not stopped, could take over a lake in little time, growing up to 20 feet from the bottom, making swimming and boating difficult.

Fish eat other plants, making room for more milfoil, and without the other plants, the fish die without food.

“[Boathouses] cause an ecological disturbance of the shoreline and fish breeding areas and, at the same time, are creating an ideal environment for milfoil that’s a problem to manage,” said Chris Devine, executive director of the Squam Lakes Association.

More than 40 lakes in the state have milfoil, and local officials work hard to keep it in check.

Center Harbor resident Kent Warner submitted a petition with 25 signatures to put the article on the ballot. Moultonborough resident Carolyn Sawin suggested the ban for her town.

Center Harbor now has about 10 boathouses; Moultonborough about six.