Tanya Snyder with Milo Evans-Snyder, 5 months old, left, Jessica Champagne with Benjamin Toth-Champagne, 3 moths old, and Jamie Davis Smith with Adam Smith, 10 months old, stand in the hallway after dozens of parents with toddlers and others sat through a D.C. Council hearing to show support for a paid family leave bill that the mayor let become law Thursday. (Jabin Botsford/The Washington Post)

A bill to offer workers in the District of Columbia some of the most generous paid family leave benefits in the nation will become law, barring last-minute intervention from Congress.

D.C. Mayor Muriel E. Bowser, who was considering vetoing the bill over its cost, has decided not to do so.

The bill now goes to Congress, as all local legislation does in the nation’s capital. While Republicans in Congress have expressed interest in overturning the city’s assisted suicide law, rolling back its gun laws and ending its legalization of marijuana, observers say they seem less likely to block the family leave law, since there is greater bipartisan support for the idea.

Bowser had voiced concerns she heard from business leaders who oppose a new payroll tax needed to pay for the benefits.

Under the legislation, passed by the D.C. Council in December, the District would guarantee more paid family leave for private-sector workers than any of the states. It would also rival legislation New York will begin phasing in next year to offer more than two months of paid leave after the birth of a child.

(Claritza Jimenez/The Washington Post)

The D.C. bill guarantees up to eight weeks of paid time off to new parents, six weeks to workers caring for ailing family members and two weeks of personal sick time. Workers could begin taking the benefit in 2020.

Bowser, a Democrat, had split from many in her party — including former presidential candidate Hillary Clinton, who praised the D.C. bill — by raising objections about the fiscal impact on businesses.

The first-term mayor signed legislation last year to raise the District’s hourly minimum wage to $15 by 2020. Bowser said she also supported the idea of family leave, but was swayed by arguments that the city needed to move more slowly to understand the combined impacts of family leave and higher wages, especially on smaller businesses.

Bowser also said the bill would send too much money out of the District, to city workers who live in Maryland and Virginia.

But in the end, Bowser appeared hesitant to test the power of her veto, as it remained unclear whether she could muster five votes needed on the 13-member council to sustain it.

The D.C. Council has shifted to the left over a series of recent elections, mirroring the progressive mind set of the city’s increasingly younger and more affluent Democratic majority.

In a letter to the council, Bowser nonetheless blasted the legislation, saying she still has “grave concerns” about its cost.

The mayor said that while she would not veto it, she would not sign it, letting it take effect without her endorsement.

Bowser also suggested continued resistance to the plan, saying she may not fund its implementation in her next budget, leaving that task to the council.

“While the legislation will advance without my signature, my administration will look to our partners on the council to provide ways to overcome the very significant deficiencies,” Bowser wrote. “The council must fund and refine the legislation before any significant outlays of resources can be made.”

Council Chairman Phil Mendelson (D) said he was thrilled that the legislation would become law and said he would entertain alternative funding schemes for the estimated $250 million annual cost of providing the benefits.

Council members Elissa Silverman and David Grosso, at-large independents who co-introduced the legislation, both celebrated.

“I’m happy for the many people who shared very personal stories with me — often heartbreaking stories — about choosing between caring for a loved one or keeping a paycheck,” Silverman said. “This program will help them weather the critical life events when they need help the most.”