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

Virginia Gov. Terry McAuliffe signed a controversial bill Friday that forces Alexandria to move faster than it planned to replace Old Town’s 200-year-old combined sewers, which dump runoff and sewage into the Potomac River after rainstorms.

The statute, pushed by lawmakers from several downstream districts, demands that the city replace the sewers at all four of its overflow sites by 2025.

Alexandria had planned to address the three outfalls that flow into Hunting Creek first, leaving work on the biggest outlet, at Oronoco Bay, until the mid-2030s or later.

But environmentalists, local residents and some legislators raised an outcry, arguing that the city should move faster on what is expected to be an expensive and disruptive project, with local tax and fee increases set to rise later this year to help pay for it.

One legislator wanted to penalize Alexandria by stripping all state funding from the city if it didn’t replace the sewers by 2021.

Virginia Gov. Terry McAuliffe (D) (Steve Helber/AP)

That provision was removed, and the deadline was pushed back to 2025.

McAuliffe (D) sought to amend the bills to give the city until 2029, but the Republican-controlled General Assembly refused to agree.

Three weeks ago, Alexandria’s elected officials asked McAuliffe to veto the bill, arguing that the 2025 deadline is unrealistic.

“The governor supports the outcome the bill is trying to achieve, and he recognizes that there are still multiple General Assembly sessions through which the city can petition for more time if they are unable to meet the deadline the bill imposes,” McAuliffe spokesman Brian Coy said.

Alexandria officials plan to work as quickly as possible to comply with the new deadline, city spokesman Craig Fifer said, although “our in-house and consulting engineers with extensive combined sewer experience have indicated that it is not feasible to complete this work by 2025.”

State Sen. Adam P. Ebbin (D-Alexandria), who led the fight against the accelerated deadlines in Richmond, said “it’s unfortunate that we’ll have a law with a timeline that experts say can’t be met. Due to the unique condition of the historic shoreline, this is no routine tunnel.”

Oronoco Bay was the third-busiest port in Colonial times and was lined by industrial plants during the 19th century.

Remnants of that period could pose obstacles to new construction that, along with federal environmental requirements, could slow the pace of building underground tunnels and storage tanks, Ebbin said.

State Sen. Scott A. Surovell (D-Fairfax), one of the legislators who sought faster action, argued Friday that Alexandria has dragged its feet on a problem it has known about for years. “Americans built the Hoover Dam in six years, put a man on the moon in eight years, and we built the Chesapeake Bay-Bridge Tunnel in 43 months,” he said. “I’m sure Alexandria can build a storage room the size of a high school gym, along with a pipe to connect the storage chamber with a sewage line, in eight years.”

McAuliffe’s decision to sign the bill was hailed by environmental activists in the state.

“This is great news for everybody who spends time on the Potomac River and the Chesapeake Bay,” said Rebecca LePrell, executive director of the Chesapeake Bay Foundation in Virginia.“Now there finally is a strict deadline for ending these sewer overflows.”