Harford's council set annual fees of $125 for every residential property and $7 per 500 square feet of commercial property covered with pavement or buildings. Boniface said he and other county lawmakers weren't happy with the fee structure, however, and decided to collect only 10 percent of it in the first year while a task force takes another look at the issue.

Boniface contended that the state could have handled the fee startup better, but added, "We're still required to meet EPA requirements. And if we don't we're opening ourselves up to pretty substantial fines, or even worse."

Jay Sakai, water management director for the Maryland Department of the Environment, said state officials decided to act after asking all the affected localities to report in August on what fees they were levying.

He said the letters to Frederick and Harford weren't meant to be threatening but "just highlighting the concerns that we have." He pointed out that the Harford letter was written in response to an inquiry from Boniface about what would happen if the fee was repealed.

Sakai said state officials don't really care about the size of the fees right now, but wanted Baltimore City and the nine largest counties to set up a means of paying for pollution control projects so they could comply with new stormwater cleanup orders due to them from the MDE by year's end.

The candidates for governor debated the state's threat of action in an environmental forum Tuesday in Annapolis

Maryland Attorney General Douglas F. Gansler declined to say whether he categorically supported or rejected the stormwater fee, which his office is enforcing, but said he thought there were a lot of other ways to pay for cleaning up the bay.

Del. Heather Mizeur, a Montgomery County Democrat, said the only way the state will be able to meet its commitments to the federal government is to require local jurisdictions to comply with the law. "We can't just pass laws. We have to enforce them," she said.

But Del. Ron George of Anne Arundel County, one of three Republican candidates, said the state is coming down too hard on local jurisdictions.

"I don't agree with how heavy-handed it is," George said. "We lose our independence as people if we lose our local locus of control."

Staff reporters Erin Cox, Michael Dresser and Pamela Wood contributed to this article.