After months of trying to impose tough new rules for how towns should manage their storm water, Pennsylvania regulators on Tuesday backed off and granted municipalities a nine-month extension for measures some had termed "draconian."

Towns were to have submitted plans by Sept. 10 detailing how they would comply with new rules to handle the gushers of rain that often flow through culverts directly into streams, carrying with them road oil, fertilizer, trash, and other pollutants.

But anxious local officials pushed back, calling it an unfunded mandate and worse.

The way they read an initial ordinance floated earlier this year, they would be forced to spend millions of dollars sweeping salt off roads after storms, installing storm-sewer retrofits, and even requiring residents to submit storm-water plans for patios.

The state Department of Environmental Protection originally resisted an extension. But in an interview Tuesday, John Hines, the department's deputy secretary for water management, said that one would be granted after all. He said he expected a formal announcement by mid-August.

"We have heard their concerns," Hines said. "But in this extension period, we all have a lot of work to do, and we need to do it together."

Pennsylvania - like other states - is trying to solve one of the thorniest environmental problems involving the nation's waterways.

Since the passage of the Clean Water Act in 1972, environmental officials have made strides in dealing with the pollution that comes from industrial pipes and other identifiable sources, called point-source pollution.

But as suburbs have grown, storm water - non-point-source pollution because it originates everywhere - has become "a bigger portion of the pollution equation," said Jon Capacasa, director of the water protection division for the Environmental Protection Agency's Mid-Atlantic region.

While many states have regional storm-water authorities, Pennsylvania must corral a host of smaller towns, each with a limited purview and, especially, limited funds.

Decades ago, most close-in suburban towns dealt with storm water as a flooding concern, installing large pipes to drain it into waterways as fast as possible.

But erosion became a problem. With algae blooms caused by an excess of fertilizers and other nutrients, populations of fish and other aquatic organisms suffered.

So, beginning in the 1980s, the preferred method was to dig a large hole - a detention basin - that would capture the initial sluice of rain, releasing it gradually.

Surveys have shown that many no longer work. They have become clogged with silt, their pipes corroded and their berms collapsed.

"If we're going to . . . have clean streams, we have to deal with the non-point-source pollution," said Robert G. Traver, director of Villanova University's Urban Stormwater Partnership. "There is not a question there."

This year, the noose began tightening.

As he learned more about the state's proposal, Michael Fox, vice chair of the Montgomery Township Board of Supervisors, became worried.

He eventually called the state's approach "draconian." He and others thought they were being asked to undo 150 years of industrialization in one five-year permit cycle.

In a township with a $12 million annual budget, the engineer told Fox it would likely cost $6 million to retrofit its 2,000 storm drains.

The way Fox understood it, anyone building a patio larger than 250 square feet - 25 feet by 10 feet - would have to hire an expert to devise a storm-water plan, adding "thousands of dollars to a project that has been a fairly humble home improvement all these years."

In addition, the township would have to inspect it regularly, and who has staff for that?

Seeking strength in numbers, Fox formed a storm-water coalition. Last week, more than two dozen municipal officials attended a coalition meeting. By then, 30 towns had passed resolutions to join the group and pledge funds, based on population.

The coalition planned to use the money for engineering expertise and, if necessary, legal fees.

Told of the extension, Fox said he was encouraged.

In New Jersey, permits issued in 2004 required 457 urban municipalities to institute a checklist of activities.

By 2008, 99 percent of the municipalities had adopted storm-water control ordinances, and 300,660 tons of trash had been removed from New Jersey streets, 1.27 million miles of roads had been swept, and so on.

But Bill Wolfe, director of the environmental nonprofit group NJ PEER, said that despite progressive components, oversight had been poor and implementation "spotty, at best."

Experts predict storm water will be at the top of the list of issues municipalities must deal with in the next few years.

"Everybody agrees on the end result," said Elam Herr, an official with the Pennsylvania State Association of Township Supervisors. The question is how to get there.

"All we know is that things are going to. . . cost more money," Herr added.

Trouble is, there isn't any.

During the era of point-source pollution, facilities got "all kinds of money" from federal and state agencies, said Jeffrey Featherstone, a regional planning professor at Temple University. Now, "the municipalities consider this an unfunded mandate."

Ed McBride, vice chair of the Upper Merion commissioners, said his township had been all but ready to lay off employees in the last budget cycle. He said the storm-water mandate would make the situation far worse.

Meanwhile, the science of storm water has changed dramatically.

It's not just pipes and holes in the ground, but streamside "buffering" with trees and other plantings to retard and absorb the runoff. Or "rain gardens" in developments to do the same thing. Or porous pavement to let rainwater soak back into the ground.

Town officials and others say they want broader fixes with more flexibility, not one-size-fits-all regulations.

A rural upstream town with more open space, for instance, could install a large infiltration area, with financial help from a downstream community with no land to do likewise.

The DEP's Hines said his agency wants to look at more options like these, focusing on results.

Last year, the nonprofit Pennsylvania Environmental Council hired Temple researchers to fan out across the Wissahickon Creek watershed and identify storm-water improvements. They came up with about 300.

"These could be bartered by the municipalities as part of a trading system," Featherstone said. "But in order to do effective trading, you have to have a good plan."