Virginia’s legislators are sounding off this session about how soon the city of Alexandria should have to end frequent overflows from its sewer system into the Potomac River and its tributaries.

The state Senate voted last week to give the city almost eight years to carry out costly upgrades to the system, a change from an original bill that would have required the city to act by 2020 or lose all state funding. A version of this compromise will need to pass the state House of Delegates.

Alexandria’s original plan to space out expensive upgrades would have taken another 20 years or more to end what amounts to routine polluting of the Chesapeake Bay tributary. The Potomac Riverkeeper Network  mounted a protest in the fall to the long timetable, and the city has since agreed to begin studying a fix for the fourth outfall in 2018, 14 years earlier than originally planned. But design and construction of the remedy still would not have begun for another decade after that — in 2028.

Alexandria Mayor Allison Silberberg (D) objected in news reports to the new 2025 deadline from state legislators, saying the upgrade will take years and cost millions of dollars. City officials have said that on the longer timetable they have proposed, the improvements will add up to $15 a month to local sewer bills that currently average $45 a month.

The city intends to ask the state for funding similar to that which the cities of Richmond and Lynchburg received to help defray the cost of fixing similar sewage overflow problems. Alexandria is one of many cities in the country with a “combined sewer system,” under which rainfall collected by storm drains is piped into sanitary sewer lines, resulting in frequent overflows during downpours. Federal regulators are pressing those communities to overhaul their infrastructure so that more polluted water can be held for treatment rather than discharged into nearby streams and rivers when sewer lines become overloaded.

Environmental groups have questioned why state and federal regulators seemed to be giving Alexandria so much time to make the changes when, just across the river, the District of Columbia has already begun building a $2.6 billion fix for its much larger sewage overflow. The work there to build 13 miles of underground storage tunnels should be complete by 2022.

The Potomac Riverkeeper Network submitted formal comments to the state Department of Environmental Quality in December requesting that a public hearing take place on the city’s plan. The group has also asked the U.S. Environmental Protection Agency to look into the city’s plan to ensure it complies with clean water laws.

The EPA wrote a letter to the city’s Office of Environmental Quality in November asking for more information about its long-term control plan for financing upgrades to the system and for proof that it complies with Section 308 of the Clean Water Act. The letter states that failure to comply with the information request could result in enforcement actions and civil or criminal penalties.

The overflow problem is caused by centuries-old infrastructure that the city has been slowly working on for decades. The city began studying its overflows as far back as the 1980s, and under a long-term control plan adopted in 1999, began to somewhat reduce the extent of its combined sewer system. Last year, the city agreed to begin planning to build storage and treatment facilities to curtail overflows from three of four outfalls where they still occur.

But, with the state’s blessing, the city planned to leave the largest outfall — which spews nearly 70 million gallons of polluted stormwater annually into the river’s Oronoco Bay — untouched for the next 20 years.

That’s too late for environmental activists and some city residents, who say bacterial contamination from the sewage overflows — which totaled 130 million gallons last year — pose health risks for adults and children who kayak, row and otherwise recreate on the river.

The Potomac Riverkeeper Network completed a review of the city’s own water quality tests from 2007 to 2012 at the Oronoco Bay outfall and found that more than half of the samples showed fecal bacteria levels exceeded state standards for safe water recreation.

A legal expert said citizens concerned about the overflows don’t have much recourse for legal action on the matter while state and federal agencies are still allowing the overflows, because the city is not violating its permit. Should lawmakers decide against funding or ordering a faster remedy, advocates for stopping the sewage discharges might have to wait until the permit is up for renewal in 2018.