Signs warn about city sewage where it enters the Potomac river at the Oronoco outfall in Alexandria, Va. (Bill O'Leary/The Washington Post)

Alexandria’s local government, stung by the General Assembly’s recent vote requiring the city to fix its sewage discharges into the Potomac River by 2024, is asking Gov. Terry McAuliffe (D) for more time to solve the problem.

At a meeting with local legislators Tuesday night, Mayor Allison Silberberg (D) said the city is “fully committed” to fixing all four combined sewage outfalls but simply cannot meet the deadline imposed by Richmond.

City Council member Redella S. “Del” Pepper (D) described the legislative action as “very punitive, mean-spirited and hateful.” Council member Paul Smedberg (D) warned of “huge financial implications” if the newly approved legislation stays as is.

“I believe in science,” Silberberg said. “And our engineers have told us emphatically that 2029 is as soon as we could get it all done — and that was a very aggressive end date.”

The city wants McAuliffe to amend House Bill 2383, which was approved by the General Assembly on Saturday, the final day of its annual session.

McAuliffe is now reviewing the bill, said his spokesman, Brian Coy, and could offer an amendment anytime during the next three weeks, sending it back to the General Assembly for its reconvened session April 5. If he does, the legislature could accept the amendment, or reject it and risk a gubernatorial veto.

State Sen. George L. Barker (D-Fairfax) told the council that one option is for McAuliffe to add a provision that allows the state Department of Environmental Quality to extend Alexandria’s deadline if necessary. Barker said when he tried to introduce such an amendment over the weekend, the legislature’s Republican majority rejected it.

Del. Mark H. Levine (D-Alexandria) called the legislation “a political effort by certain members to tar Alexandria,” noting the city’s wealth in comparison with the rest of Virginia and its status as a liberal enclave in what is still a politically divided state.

But Sen. Richard L. Saslaw (D-Fairfax), the Senate minority leader, told city lawmakers there’s far less anti-Alexandria feeling among legislators now than when he began serving in Richmond in 1976. “We’ll get through this,” he assured council members. “We’ll get something worked out.”

Like about 800 other old cities in the United States, Alexandria has combined sewer pipes, which handle both rainwater and the effluent washed down sinks and toilets. Whenever it rains more than a trace, storm water runoff combines with sewage and overflows into the Potomac River at four separate discharge points. The pollution rankles environmentalists and communities located down river, in Fairfax County and beyond.

Responding to legal requirements from both state and federal authorities, the city last year approved a $188 million plan to capture runoff from three of the four discharge pipes, contain it in giant underground holding tunnels and tanks and send it to the local wastewater treatment plant before discharging the cleaner water into the river.

But that plan did not address the biggest source of sewage, the Oronoco outfall, which enters the river at the foot of Pendleton Street. City officials say the outfall spills 11.3 million gallons of raw sewage — or 70 million of combined sewage and rainwater — into the river each year.

Alexandria initially said it would launch a study of possible solutions in the mid-2030s, after the other overflow sites were fixed. After some residents objected, the city accelerated its response by 14 years.

By then, it was too late. Lawmakers from Fairfax and farther south began filing bills in Richmond demanding that Alexandria live up to its “eco-city” nickname. One would have required Alexandria to fix the sewers by 2020 or lose every cent of state funding it receives for schools, roads, affordable housing and other needs.

The sewer fixes will be expensive for taxpayers, say Alexandria officials, who have already announced a sewer rate hike for the coming fiscal year. Last week, City Manager Mark Jinks proposed a new storm water utility fee, which would cost homeowners an average of $70 in the first half year it is deployed. Both changes would generate revenue to help defray the cost of bonds to pay for the city’s first tunnel and tank project.

Ultimately, officials say, the initial project will probably add an additional $10 to $15 per month to the average residential sewer bill, which now ranges from $45 to $60. A similar fix at the Oronoco site probably would add another $12.50 a month.

State Sen. Adam P. Ebbin (D-Alexandria) noted that the state has given about $97 million in loans and grants to the city of Richmond and about $180 million to Lynchburg to help address their combined sewer system repairs.

Alexandria officials vowed to ask the state next year for similar financial help.