Some state lawmakers have complained fees set by the localities are exorbitant and want to revisit the issue in the General Assembly session that begins this month.

Environmental advocates have also questioned why Baltimore County allowed many projects to proceed using older, less effective controls on pollution.

Criticism has been led by Klein, an Owings Mills resident who is president of Community and Environmental Defense Services. Klein conducted research for a group of environmental organizations, including the Chesapeake Bay Foundation and the Greater Baltimore Group Sierra Club.

Klein found the county has issued hundreds of waivers since 2010 and that about one-fourth of more recent projects approved by the county's administrative law judges are employing the environmental site design process. He also noted the county has reduced its staff assigned to review developers' stormwater control plans.

Officials in Carroll, Harford and Howard counties say they've also issued waivers for most projects that were already in the pipeline but require all new projects to use environmental site design concepts.

"We actually are seeing some of the grandfathered ones ... come in and use the new rules, which is a good thing," said Marsha McLaughlin, director of planning and zoning in Howard County.

Baltimore County's Gardina said the county lost three reviewers during an early-retirement initiative in early 2012 and that the department now has four full-time reviewers and one person who can perform inspections and reviews. But he defended the county's record.

"We've tried to use environmental site design where it's applicable and will have a good benefit," Gardina said. "Environmental site design is not a panacea. ... It depends on the hydrology of a particular site."

Michael Harrison, vice president of government relations for the Home Builders Association of Maryland, said environmental site design usually costs more for developers. "Sometimes, it evens out," he said. "Most of the times, it's more expensive."

Sakai defended the county's enforcement of stormwater regulations, calling its program "robust" and well-funded.

He also said the degree to which new development can be required to use environmental site design practices depends on soil type and topography, which vary across the state.

Roughly 55 percent of Baltimore County's soils can easily absorb runoff, compared with 61 percent in neighboring Harford County, according to data compiled by the U.S. Department of Agriculture's Natural Resources Conservation Council. But the difference is far smaller than the number of waivers issued would suggest, Klein says.

The state environment department has been focused on drawing up new stormwater control "permits" for the state's largest communities — part of a separate federal mandate regarding control of runoff from existing development as well as new construction.

More than three years late in meeting federal deadlines for the permitting process in Baltimore County, Baltimore City and Prince George's County, the state environment department issued new permits in late December. The state still must finalize permits for six other large counties.

Once those are in place, Sakai said, state staff can start to hold local officials accountable for performance. In the meantime, he said, his staffers have been meeting with local officials about the updated state stormwater regulations and a new manual on approved practices for handling runoff.

"This is a process," Sakai said. "If in fact there are discrepancies … or misunderstandings that are apparent, or deficiencies that are apparent in the way any local program is being run, I do agree that it's incumbent on us to get to the heart of that matter.

"But we've been going about this in a well-thought-out way," he said. "The approach here is not to go rushing in, counting waivers and decide if a program is good bad or indifferent."

Prost acknowledged Baltimore County has been a leader among localities in the state in restoring streams and taking other steps to reduce runoff from older existing communities. But she said environmental groups want to hear from county officials why so few new development projects are being required to make full use of the latest stormwater control techniques.

"Help us understand why this was justified," she said.

And she said the state needs to fulfill its legal responsibility for overseeing local performance "to make sure that new projects going forward don't have an impact."