There is a rain garden next to the Lawrenceville building that houses 3 Rivers Wet Weather.

So when rain falls, much of it flows into the 200-square-foot garden, said John Schombert, the environmental group's executive director. And that means not as much ends up in the region's sewer system.

It's a small example, but interest in the approach -- incorporating so-called green elements along with "gray" infrastructure such as bigger sewer pipes -- seems to be taking firmer root in the region. In recent weeks, political leaders, community groups and residents have lauded the environmentally friendly approach as a more cost-effective way to correct a sewer system overflow problem whose proposed $2 billion fix has loomed dauntingly for more than a decade.

"We're looking at this, for the region, as a big window of opportunity," Mr. Schombert said. So, too, is the Allegheny County Sanitary Authority, the agency tasked with devising a plan for wet weather management.

It's a window that, for quite some time, did not seem nearly as open.

A 2008 federal consent order mandated that Alcosan eliminate all illegal sanitary overflows into the Pittsburgh region's rivers and reduce overflow from combined sewers by 2026. The $2 billion wet weather plan that Alcosan unveiled in July 2012 proposed addressing the region's wet weather needs using predominantly gray infrastructure, such as underground storage tunnels and bigger collection pipes to prevent untreated sewage from overflowing onto streets and into streams.

That was partly because understanding and acceptance of green infrastructure did not begin until late in a planning process that dates back to 2000, said Arletta Scott Williams, Alcosan's executive director. Also, federal guidelines were clear that Alcosan could not build its plans on components it could not ensure would be implemented, such as green infrastructure projects in individual municipalities.

But recently, and in the past two years especially, there's been a movement from gray toward green infrastructure, which could include components such as green roofs, rain barrels, rain gardens and porous pavement.

Alcosan, after unveiling its gray-only wet weather plan in July 2012, received numerous public comments urging the organization to add green infrastructure and source reduction to its wet weather plan. Allegheny County Executive Rich Fitzgerald and Mayor Bill Peduto have urged the same, Ms. Williams said.

And that was why, when Alcosan submitted its original wet weather plan in January 2013 to meet the EPA's deadline, the agency also asked for an extension to study further the possibility of incorporating source reduction, which refers to efforts to prevent stormwater from entering the sewage system in the first place.

The extension wasn't granted, but Alcosan still embarked on a source reduction study that is ongoing and that has included input from groups such as 3 Rivers Wet Weather, Ms. Williams said.

A turning point came in late January, when the U.S. Environmental Protection Agency informed Alcosan that its wet weather plan was deficient, adding that the U.S. Department of Justice would be in touch. The Justice Department then told Alcosan last week that the agencies were willing to modify the consent decree to consider a wet weather plan that consisted of a phased approach involving flow reduction, green infrastructure and a regional approach.

Members of Pittsburgh's congressional delegation in Washington, D.C., who had been lobbying for the Justice Department move, described it as a chance for Alcosan to incorporate green infrastructure while protecting low-income ratepayers. Alcosan increased its rates by 17 percent in 2014, with 11 percent increases planned for 2015 through 2017.

Ms. Williams, in an interview Thursday, confirmed that Alcosan was still planning to implement source reduction and green infrastructure components into a revised wet weather plan, now that it appears the agency has been given the chance to do so. But she said it was still "a little premature" to say what those green components would be, or how they would fit in the original wet weather plan.

"We're still in the relatively early stages of the study that we embarked on late last year to investigate green infrastructure options and source control," she said.

It was also too early, she said, to speculate on what a revised plan could mean for ratepayers.

But environmental groups said deciding to incorporate green infrastructure is a good first step.

"Green infrastructure has proven to solve water quality problems, manage stormwater and create other environmental benefits like cleaning the air," said Emily Alvarado, interim director of the Clean Rivers Campaign, a coalition of environmental groups, community groups, faith groups and ratepayers that has been vocal in calling for a "green first" approach to wet weather management.

Also crucial is source reduction, or limiting the amount of water that is entering the sewer systems, and giving communities an incentive to do so, said Davitt Woodwell, executive vice president of the Pennsylvania Environmental Council.

"This is something that we've lived with for a while, we'll live with for a while more, and we just really need to be open to taking new approaches to dealing with this," he said.

Nationally, going green when it comes to sewer system management has become vogue.

"The momentum has been building in recent years, because people are looking at green infrastructure as being a lower-cost alternative," said Kari Mackenbach, National Green Infrastructure Practice Leader for URS Corp.

Ms. Mackenbach has her office in Columbus, Ohio, a city that recently worked with the federal government to revise its consent decree to incorporate more green infrastructure and source control. Other cities, including Louisville, San Francisco and Kansas City, Mo., have pursued similar green and gray approaches in recent years, she said.

Due to its topography, incorporating green infrastructure likely will be more challenging for Pittsburgh, but Ms. Mackenbach, a Murrysville native, believes the area "is ripe for these opportunities."

Still, she said, green infrastructure is "not a panacea." The region will still need a robust gray infrastructure.

"It is a tool in a toolbox that all communities should consider," she said. "But it's not the end all, be all."

Here in Allegheny County, Etna is one community that has been reaching into its toolbox frequently.

The borough, located along the Allegheny River, has a history of flooding and is "conscious, very conscious," of stormwater, borough manager Mary Ellen Ramage said. In recent years, the community has focused on source control and green infrastructure as a way to address flooding, with a "green streets" program underway to add components such as permeable sidewalks and parking lots, as well as a nearby "rain park" to absorb water runoff.

"We just have to train ourselves to change," she said. "Maybe instead of constantly cleaning out people's basements, we have our Public Works Department maintaining rain gardens and bioswales and cisterns." Bioswales are typically a vegetated area designed to catch rainwater and also absorb it; cisterns are storage tanks to collect water, such as that falling from a roof.

But it can't just be one community's Public Works Department.

In recent weeks, the message, from the Justice Department to the EPA to Mr. Fitzgerald to Mr. Peduto to Ms. Arletta, to environmental and community organizations, is that the approach to stormwater management must be a regional one, because Alcosan cannot implement green infrastructure on its own.

Eleven months ago, a committee of local municipal leaders convened by the Allegheny Conference on Community Development endorsed the regional approach and recommended the county appoint a coordinator, but that hasn't happened yet.

Part of the challenge in a regional approach will be finding incentives for local governments to draft ordinances and regulations to make their communities more stormwater friendly. That included figuring out how to ensure that structures such as parking lots, which don't have a sewer bill but do contribute to runoff, also contribute to fixing stormwater problems, said Mr. Schombert, the 3 Rivers Wet Weather executive director.

It is largely, he said, "generational changes" to the way communities handle rainwater.

"The real responsibility for instituting green infrastructure has to be at the community level," he said.

First Published: February 16, 2014, 4:56 a.m.