PALERMO — Summer resident David Tyndall took one last shot Thursday night at keeping his treehouse, but in the end agreed to remove it by September.

On Friday, according to Town Clerk Sheila McCarty, Tyndall signed a consent agreement previously approved by selectmen that allows Tyndall to keep the treehouse, which the code officer says is an illegal structure, until Sept. 1. If Tyndall removes it by the deadline, town officials will take no further action.

Tyndall built the treehouse without a permit 93 feet from Sheepscot Lake, according to Code Enforcement Officer Darryl McKenney.

Since Palermo ordinances prohibit structures within 100 feet of the water, McKenney ordered it removed.

McKenney told Tyndall he could not grant an after-the-fact permit. The Board of Appeals ruled that Tyndall did not meet conditions for a waiver of the 100-foot requirement.

At Thursday’s selectmen’s meeting, Tyndall asked whether a treehouse is a structure, and how the distance from the water should be measured when a lake’s level is affected by a dam.

McKenney said that a treehouse meets the definition of a structure in the town ordinance.

Setback is measured from the high water mark, as indicated on the shoreline, to the closest part of the structure, regardless of whether the lake level is natural or controlled by a dam, he said.

Under a recent court decision, McKenney said, a board of appeals cannot rule on those kinds of questions when a violation is involved. If Tyndall does not accept McKenney’s opinion, his recourse would be to go to court. Tyndall said he does not intend to go to court over the matter.

In other business, McKenney, speaking for the town’s assessors, recommended that selectmen set the 2011 tax rate at $11.50 for each $1,000 of valuation, a drop of $1 per thousand from the 2010 rate.

“I think it’s good news,” board member Harry Dean Potter said as the board unanimously approved the recommendation.

McKenney said tax bills are ready to be mailed.