The permit would apply to “a whole new universe of permit holders who have never been regulated before,” Houlihan said.

The results could be visible in water quality tests within three to five years after the permit is finalized, he estimated.

Affected sites should “develop plans to reduce pollution” and “implement stormwater controls such as sweeping parking lots, installing rain gardens and other stormwater management methods,” according to the EPA.

“Another, perhaps more cost-effective way to address this permit is to remove your impervious cover and allow the natural process of infiltration to take place and restore the natural hydrology of the area,” Houlihan said.

The federal agency estimates that the permit, as currently written, could be required for approximately 511 commercial, 394 industrial and 88 institutional properties in the Mystic River watershed, according to Houlihan. In the Charles River watershed, this could apply to approximately 1,867 commercial businesses, 81 industrial businesses, and 347 institutional institutions. And in the Neponset region, affected sites could include 470 commercial sites, 253 industrial sites and 104 institutional establishments.

Executive directors of the Charles River Watershed Association, Mystic River Watershed Association and Neponset River Watershed Association praised the EPA’s action Thursday.

CRWA leader Emily Norton called it “a major step in shifting responsibility where it belongs”, and NRWA president Ian Cooke said “many people don’t realize that the majority of Sidewalks that contribute to the polluted runoff problem are private parking lots, roofs and driveways” – impervious surfaces that would be treated under the EPA permit.

But the three nonprofits took issue with the EPA’s slow implementation, a years-long process under the proposal on which the EPA is seeking comments. The agency has planned a phased implementation that calls for all stormwater controls to be implemented within 11 years of permit approval.

“We urge the EPA… to significantly accelerate the proposed compliance timeline so that the public can more quickly enjoy the benefits of a clean, swimmable Charles River,” Norton said.

“While we are pleased to see EPA moving forward to address these important challenges, the issue calls for more urgency and it is possible to take these common-sense steps well before 2035,” Cooke said.

Patrick Herron, Director of the Mystic River Watershed Association, added, “Our communities should not have to wait another 11 years for clean drinking water. »

The permit project is the “result” of a Trial 2022 filed by the Conservation Law Foundation and CRWA, according to CLF, which said rain and melting snow send oil, grease, chemicals and waste from large paved areas into the three rivers.

CLF predicted the permit would require big-box stores, malls and private universities to reduce stormwater runoff, such as “street sweeping and trash collection or structural changes like ponds, rain gardens and gravel wetlands.”

“After five years of petitions and a lawsuit against the EPA, we are pleased that these federal protections have come to fruition,” said CLF Vice President Heather Govern. “But the EPA permit allows for an 11-year delay before these rivers experience a significant positive impact. As pollution and intense storms increase in the Boston area, the Charles, Mystic and Neponset rivers can’t wait that long.

Houlihan told reporters Thursday that he expected a lot of feedback on the timeline, which he said fits the overall Charles River cleanup timeline, and that the EPA could adjust its plan based on public comments.

“We think what we’ve proposed is a reasonable timeline. Take into account that this is a whole new universe of licensees that have never been regulated before, and that the industry itself- even needs time to develop and prepare to make some of these improvements, and that it would be a phased approach over many years to tackle the larger properties first and then the larger ones. small properties later,” Houlihan said.

A 90-day public comment period will run through January 29, including two Zoom briefings in early January and two Zoom public hearings to receive comments on January 22 and 23.

The agency pointed to a similar permit implemented in southern Maine in 2015 and said the Rhode Island Department of Environmental Management would submit a draft permit for public comment this fall.

The EPA considers all three rivers – Charles, Mystic and Neponset – “impaired” due to both bacteria and nutrients like phosphorus.

“So we want to make sure that the goal of the Clean Water Act — fishable, swimmable waterways — is achieved,” Houlihan said.