The State Water Control Board will initiate enforcement procedures against Prince William County unless it stops dumping excessive amounts of pollutants into Northern Virginia waters, a senior state official has warned.

Regional director Tom Schwarburg, in a letter to the county last week, said that effluents from the county's new waste water treatment plant contained more phosphorus during February and March than the state allows.

He warned that should the county violate those standards during April, the state will take action. By law, this could result in a fine of up to $10,000 for each offense, with each day constituting a separate offense.

Schwarburg's letter was addressed to Raymond Spittle, director of the county's major sanitary district and overseer of the operation of Prince William's new H.L. Mooney waste water treatment plant.

Spittle refused to say last week how he would respond to Schwarburg's letter. He also declined to discuss why the violations occurred.

However, he noted he is a subordinate of the county's Board of Supervisors, which passed a resolution Jan. 18 instructing him to reduce the amount of chemical treatment at the plant.

The warning came about the same time Prince William adopted new, less stringent pollution control standards that it had previously negotiated with the state board.

According to County Board Chairman Kathleen Seefeldt, the February and March violations were allowed to occur because the county was anticipating that those new standards would be in effect. However, there was a two-month delay before the county formally adopted the new standards.

"In the interim, we felt it was ridiculous to treat to a standard that would be altered," she said.

Seefeldt said she thought that when the supervisors finally approved the new standards in a meeting last week the county would no longer be in violation because the new limits would match those now being met at the Mooney plant.

Schwarburg, however, said the county remains subject to the old standards until the control board formally issues the new permit.

The officials said the county faces a waiting period of at least 30 days before the new, more lenient permit can be issued because of a requirement to give public notice of a permit change. Other bureaucratic channeling that would send the matter to Richmond and back could add another two weeks to a month before Prince William is given the new permit.

Schwarburg wrote he viewed the county's action as "deliberate" and it represented "willful violation" of water standard limits.

"If the violation continues into the month of April, we will begin preparation of permit enforcement before our board at its regularly scheduled meeting," Schwarburg wrote.