The charter amendment on the budget was approved by 83 percent of voters in a Tuesday special election that drew a 10 percent turnout, the Board of Elections said that evening.
The amendment is part of the 68-square-mile (177-square-km) district's argument that it needs more self-government. Congress may overturn local laws, and the district has a nonvoting representative in Congress and no senators.
The amendment sets a 30-day limit for congressional review and modification of the District of Columbia's budget. After 30 days, if Congress takes no action, the budget would take effect.
Voters also returned interim District Councilmember Anita Bonds, a Democrat, to an at-large seat, election results showed.
The seat became vacant when former Chairman Kwame Brown pleaded guilty last year to a federal charge of overstating his income in applying for bank loans. At-large Councilmember Phil Mendelson was appointed chairman, and Bonds took Mendelson's seat.
(Reporting by Ian Simpson; Editing by Barbara Goldberg and Lisa Von Ahn)