The Prince William County Board of Supervisors created a water and sewer agency last night despite a last-ditch effort by some county residents to have the matter decided at a referendum.

The board's vote was unanimous, and supervisors said the agency will streamline county administration and save money.

Citizens favoring a referendum had collected 2,122 signatures on a petition. But to force a referendum they needed 4,500 before the supervisors held last night's hearing on the matter.

Board Chairman Kathleen K. Seefeldt had said earlier the supervisors wanted to avoid a referendum in this election year because "it would become a political issue." All seven supervisors are up for election this year and several of the residents who sought the referendum said they may run for the board.

Claude Bradshaw, a referendum backer and one of the prospective candidates, said residents should be able to vote for the authority because they will be affected by it.

Bradshaw said after the vote he and other residents will attempt to appeal the supervisors' decision.

The county now has four separate water and sewer districts and a handful of private firms serving 83 percent of the county's population.

The new Water and Service Authority, run by a five-member board to be appointed by the supervisors, will oversee all of the county's water, sewer and trash collection service. The authority will have the power to set water rates and to improve and expand service under contracts established by the supervisors.

Last night's hearing, which preceded the supervisors' vote drew more than 50 speakers, most of whom spoke in favor of a referendum. Many said they only recently became aware of the proposed authority and want time to study the issue. The board began studying an authority last summer.