Residents thought they struck a blow against over-regulation, but a recent vote may have jeopardized federal flood assistance for some.

Voters at November’s Special Town Meeting defeated a measure to reinsert language into the town’s flood plain district bylaw.

The Planning Board and the Conservation Commission put the proposal together to correct a mistake made at Annual Town Meeting. Due to a computer error, one page was omitted from the bylaw, which was approved without opposition at the spring meeting.

Without the language, it’s unclear what the implications are for homeowners in the town’s federally designated flood zones.

Town Counsel Blair Bailey was unavailable for comment, but at Special Town Meeting he noted, “This language is required by federal law for FEMA programs. Without the language, residents in flood plains are not eligible for FEMA relief.”

Officials were surprised by the vote.

Conservation Agent Laurell Farinon said those against the correction may not have understood the purpose of the vote. Resident Joseph Yates spoke out against the measure. He said the town had enough regulations.

“This language did not represent an expansion of jurisdiction by any means,” Farinon said. “Town Counsel will be taking a look at how this affects the town, and I’m sure we’ll be bringing it back to Town Meeting for a vote.”

Adopted in 1982, the flood plain bylaw is updated regularly to meet federal standards.

The bylaw is essentially a map that identifies flood risks for certain areas of town. The risk areas are determined by FEMA to support the National Flood Insurance program. The guidelines determine where flood insurance is required. Homeowners in floodplains must purchase insurance through the federal insurance program to satisfy mortgage holders.

The omitted language described permitted uses in flood plain areas related to agricultural, forestry, wildlife management and other areas.

In Rochester, a large area of land surrounding Doggett Brook and the town’s northeast corner are in flood plains.

Planning Board member Susan Teal said interest in the Community Preservation Act likely drew a larger than usual crowd.

Voters defeated the measure, which would have asked residents to adopt the act  at the next town election.

The act would have raised local taxes by 1.5 percent. About 350 people arrived for the meeting – one of the most well-attended Teal has seen in 34 years.

But it appears that the strong anti-tax and anti-regulation sentiment also derailed the flood plain update.

“This was not a typical Town Meeting audience. A lot of people were there because of the [Community Preservation Act],” Teal said.

Had voters known the effect on resident’s ability to get insurance, the outcome might have been different, she said.

“I think the failure of the flood plain bylaw was just a fluke,” Teal said. “I think the folks who were proponents were ill-prepared to deal with the opposition. It came as a real surprise when it failed.”

Teal said Town Counsel will be consulted. “He’s going to figure out how residents  who live in the affected areas can qualify for insurance because we just made it impossible for them,” she said.

Planning Board Chair Arnie Johnson said he too thought voters would easily approve the update. He said “ignorance” on exactly what was being voted on may have led to its defeat. The vote required a two thirds majority to pass. It was defeated by a vote of 134 to 70.