Prince George's County could grant sewer hookups to as many as 1,700 homes in the largely undeveloped southern end of the county as a result of a new agreement with Charles County on the use of the Mattawoman sewage treatment plant.

The tentative agreement, which was disclosed to the County Council yesterday, was reached last Friday after months of controversy over use of the treatment capacity at the plant, which opened in northern Charles County last March.

The dispute between officials of the two counties had taken on the aspect of a development war as Charles County commissioners claimed they needed all the plant's treatment capacity for their county's growth, while Prince George's officials insisted they had been promised treatment capacity when the plant was funded by the state.

The new treatment capacity would allow Prince George's to grant sewer connections to hundreds of homes in Accokeek and Brandywine that currently use septic tanks that have had severe overflow problems.

The new sewage capacity also would enable Prince George's to forestall construction of a $1 million sewage pumping station in the southern part of the county that was planned as an alternative to Mattawoman sewer lines.

And though new development in southern Prince George's is opposed by many citizens and has been discouraged by the County Council, the 600,000 gallons a day of sewage treatment allotted to the county could allow developers to proceed with longstalled construction plans, including a regional shopping center planned along Rte. 5 near the Charles County line.

But officials from both counties still face a remaining obstacle before the agreement can be formalized. A Charles County developer who would like to be allocated capacity at Mattawoman has filed a lawsuit that seeks to stop Charles County from entering into the capacity-sharing agreement with Prince George's.

The developer has applied to the state for a permit to discharge sewage into the St. Charles City lagoon, however, which would eliminate his need for use of the Mattawoman plant and lead him to drop his suit, county officials said.