The Leesburg Town Council has voted to ask developers to help pay for additional schools that might be needed as a result of new subdivisions.

After weeks of discussion, the measure passed at the council's meeting Tuesday night by a vote of 6 to 0. Council member Fernando J. "Marty" Martinez was absent. The town will ask developers who request higher residential density to make a proffer of a specific amount for each house, townhouse or apartment above what current zoning allows.

According to the new guidelines, which are identical to those used in Loudoun County, a developer will be asked to pay $29,750 for an extra single-family house, $15,619 for an extra townhouse and $7,809 for an extra apartment.

Because a proffer is voluntary, the Town Council cannot force developers to pay extra fees or deny a rezoning application if a developer ignores the guidelines. The town, however, could turn down an application if the council thinks the developer is not doing enough to offset the overall impact of the proposed development, said Liz Whiting, Leesburg's interim town attorney.

Tuesday's resolution is effective immediately and could be applied retroactively if a developer requests an amendment to a rezoning that increases the number of homes. For example, if a developer with 1,000 homes already approved applies for an amendment to add 200, the additional homes would be subject to the guidelines.

The resolution cites a calculation by Loudoun County public school officials that, on average, each new house adds 0.8 children to the school system, each new townhouse 0.42 children and each new apartment 0.21 children.

In April, Board of Supervisors Chairman Scott K. York (I-At Large) wrote a letter to Leesburg Mayor Kristen C. Umstattd urging the town to adopt the county's proffer guidelines to help defray the county's costs associated with growth.

At a meeting last month between the Town Council and the Board of Supervisors, county officials again asked the town to take action to alleviate the toll of development on the county.

On Tuesday, the council did not vote on a broader change it had been considering: to adopt guidelines for developers to pitch in for such expenses as police and parks. That plan was put aside for now because it was unclear how much of such costs are borne by the county and how much by the town.

Steve McGregor, a planner for the town, said town staff would study those costs and possibly prepare a proposal.

"There's more analysis to be done to see how other facilities might be shared by the town and the county," he said.

Supervisor Jim E. Clem (R-Leesburg) said in an interview that he was pleased to see Leesburg thinking about how development in the town affects the county. "If they start out by adopting the school factor, that's tremendous right there," said Clem, who is also a former Leesburg mayor. "It's probably something they should have been doing a long time ago. . . . I'm hoping all the towns will adopt that."

Town Manager John A. Wells said at the council's Monday night work session that he would work with the county to ensure that the developer fees reach their intended destination.

"We would want to have the comfort of knowing the dollars are going toward a school that's serving Leesburg residents," he said.