Selectmen on Monday voted to seek Town Meeting approval for spending about $6.4 million to filter water coming from two town wells. The Kane Well has been offline except for emergencies since last month, due to high manganese levels. Residents on the east side of town, where the Cranberry Well is located, have complained of rust-colored water due to iron. Paul Blazar, Hudson’s executive assistant, said paying for the improvements would add about $53 to the annual bill for the average residential water user, a 17.6 percent increase. This year’s annual Town Meeting convenes on May 6.