The City of Savannah could have to pay about $25 million to comply with new federal water regulations.
The costs will be passed on to water users.
The Environmental Protection Agency expects to finalize soon new rules on how much waste the Savannah River can take.
City officials say, that will require water facility upgrades.
Savannah Riverkeeper Tonya Bonitatibus says, city residents won't be the only ones paying.
"Augusta will have to upgrade. All of the industries, you've got DSM Chemical, International Paper, the sugar refinery," Bonitatibus says. "All of these guys are going to have to drastically reduce what they put in the river."
The EPA could reduce the amount of oxygen-depleting waste in the river by two-thirds.
But the agency also proposes a lenient timeline and cap-and-trade system to let a private market determine aspects of the new oxygen limit.
"It's going to be a burden on everybody because as all of the industries and all of the wastewater treatment plants have to reduce what they put into the river," Bonitatibus says. "There's a cost that's associated with that."
The amount of waste in the water is a prime determinant of the river's overall health.
Last week, a fish kill at Savannah National Wildlife Refuge was blamed on lack of oxygen in the river.