Maine and Vermont are moving ahead of other states on regulating pollution in storm water running off roofs and parking lots, which often carries oil and other toxic substances.
Vermont last week became the second state, following Maine, to change regulations designed to reduce runoff entering streams and other water bodies after heavy storms.
The states already regulate several aspects of storm water, including those from new projects and construction sites. The new rules are expected to affect already existing commercial and residential developments, some in place for decades.
"This is different in that it looks at development that actually predated the program," said Don Witherill, director of Maine's Division of Watershed Management.
The new regulations apply to property owners in watersheds of streams that don't meet water-quality standards due to storm runoff pollution. It requires these property owners to get special permits.
A permit could require property owners to make improvements like installing grassy areas to absorb runoff from paved areas, holding ponds or taking other measures.
Homeowners living very near the affected streams _ for now, five in Vermont and one in Maine _ would be required to comply by taking steps such as making sure roof gutters aren't draining onto paved areas or cleaning up pet waste in their yards.
Jennifer Callahan, an environmental analyst with Vermont's Department of Environmental Conservation, said that Vermont violators could face fines.
Establishing new regulations comes as attention grows around the country to polluted storm runoff. Part of the concern is prompted by fears that climate change is bringing more intense storms.
Environmental group officials said Monday the 1972 Clean Water Act has been successful in addressing industrial water pollution and improving treatment of municipal sewage.
"Some sources of pollution actually are decreasing in the United States," said Nancy Stoner, head of the water program at the Washington-based Natural Resources Defense Council. "But storm water pollution continues to grow because we're continuing to develop."
Not everyone was happy with the new permit system. Joe Sinagra, executive officer with the Homebuilders and Remodelers Association of Northern Vermont, said the rules would add significantly to the cost of redeveloping blighted commercial properties.
Sinagra cited a two-thirds-empty South Burlington shopping plaza. "A number of people now have looked at the property as a potential redevelopment. But the cost of doing so is astronomical because of the need to bring it up to these new standards," Sinagra said.
Witherill said Maine's regulations won't be cost-free, either. They'll require a group of property owners in the Long Creek watershed, near Portland, to chip in $3,000 per year per acre of impervious surface _ like parking lots _ into a fund dedicated to paying for projects to reduce storm water flowing into the stream.
Officials in both states said holding ponds and grassy areas designed to absorb water flowing off of parking lots are two of the methods commonly used to reduce storm runoff flowing into streams.
Stoner said it's expected a similar regulatory system may be set up to reduce storm water flowing into Chesapeake Bay, but, "It appears that New England is ahead on the issue."
Callahan said of the effort to impose new regulations on existing developments, "It's going to be a nationwide thing. Other states just haven't gotten there yet. I'm not sure why we're at the cutting edge, but we are."