The nation's capital is poised to join the state of California and numerous other cities that have approved a $15-an-hour minimum wage.

The D.C. Council will vote Tuesday on a bill that would raise the city's minimum wage to $15 an hour by 2020. The bill is expected to pass and Democratic Mayor Muriel Bowser has pledged to sign it.

The District of Columbia currently has a $10.50 minimum wage that will rise to $11.50 in July under legislation signed in 2014 by Mayor Bowser's predecessor, Vincent Gray.

This year's debate over wages centered on how to guarantee minimum-wage compensation for workers who rely on tips. The current bill raises the tipped minimum wage to $5.55 an hour, but some Council members still want to change that.