By almost any measure, Baltimore's Inner Harbor is one of the most polluted water bodies in the Chesapeake Bay - a repository for frequent sewage spills as well as stormwater laden with contaminants and metals and trash flowing in from points upstream. Its watershed is packed with people and industrial sites; its cleanup has been largely overlooked; and its prospects for anything resembling a recovery slim are slim at best.

But change is in the air for the harbor, which has been the center for much of Baltimore's redevelopment.

A coalition of residents, business owners, neighborhood leaders and city officials has launched the Healthy Harbor initiative, a plan to make the Inner Harbor fishable and swimmable by 2020. The Baltimore Waterfront Partnership is launching the communitywide effort, and invited interested parties to a daylong conference in February at the Legg Mason building in Harbor East.

More than 360 people attended; dozens more were turned away for lack of room. Among the topics discussed were paying for the cleanup, fixing aging sewage systems, creating a stormwater authority, making more attractive streetscapes with trees and islands of green space, and investing in green roofs.

Already, the city's five watershed groups have merged into one, Blue Water Baltimore, with the aim of giving the city a stronger voice in Annapolis and beyond when it comes to funding for cleanup programs.

"You see something that can be solved if people put their minds to it," said Michael Hankin, the chair of the Baltimore Waterfront Partnership and CEO of the investment firm Brown Advisory, which has its headquarters along the harbor. "Here, businesses are right on the water. We stare at it every day. We're not going to keep our businesses here, we're not going to come down here to eat if we're looking at a dirty harbor."

But progress will be a long haul. The Waterfront Partnership, which is funded through a city tax on harbor businesses, recently contracted with the University of Maryland Center for Environmental Science's Eco-Check to score the harbor. Heath Kelsey analyzed the water quality from the one monitoring station in the harbor. He looked for nitrogen, phosphorus, chlorophyll a, dissolved oxygen, toxicants, bacteria and trash. In each area, Kelsey said, the harbor scored either poor or very poor.

Several years ago, the city of Baltimore entered into a nearly $1 billion consent order with the EPA to fix failing sewage infrastructure. It has made progress, according to Maryland Department of Environment Acting Secretary Robert Summers, but not enough.

"We've got the consent order to fix the big leaks, but we've got little leaks as well," he said. "We even had wooden sewer pipes at one point. We just haven't maintained our infrastructure properly."

Summers said his department is keeping after the big polluters too, and their emissions are declining. But the progress is not enough for some environmental groups. Last July, the Baltimore Harbor Waterkeeper and the Chesapeake Bay Foundation filed a lawsuit against the current and previous owner of the Sparrows Point steel plant, Severstal N/A, and ArcelorMittal.

The groups allege that despite a 1997 consent decree with Summers' department, the owners have failed to address toxic pollution at the plant southeast of the harbor. On the southwest side, the harbor and the Patapsco River have to contend with emissions from plants in Curtis Bay and northern Anne Arundel County.

But urban waterways elsewhere have come back from such pollution, and those who have led those efforts say there's no reason the Inner Harbor can't do the same.

Consider the Charles River in Boston. In 1991, the river was a fetid mess. The Charles River Watershed Association began a data-driven restoration project, monitoring 37 sites along the 308-squaremile river basin. They hired scientists and engineers, built their own lab and worked closely with EPA leaders. They found the problems included unmapped pipes, combined sewage overflows, pipes that didn't connect, and failed infrastructure.

In 1995, the association declared a goal of making the river fishable and swimmable by 2005, according to executive director Bob Zimmerman. With support from the association and the universities and nonprofits in town, the federal government told all 208 companies that fronted the river that permit requirements would be strictly enforced and regulators would be stopping by shortly. The city updated its infrastructure. By 1999, most of the river met boating standards. Two-thirds of it met swimming standards. Now, the river hosts a swim every summer.

Other urban systems, including the Elizabeth River in Norfolk and the Anacostia in Washington, DC, have also made progress clearing away trash and working with property owners to reduce pollution. Their stories gave the Baltimore harborites hope, but also reinforced what a long slog the cleanup will be.

"It is so much bigger than us," said Congressman Elijah Cummings, a Baltimore Democrat who has been a forceful advocate for clean water. "I'm not here to ask you, because asking is so cheap. I'm here to beg you. Do not underestimate your leadership on this issue."