Democratic nominee for D.C. mayor Muriel Bowser; independent mayoral candidate David Catania. (Melina Mara; Sarah L. Voisin/The Washington Post)

With five months before the Nov. 4 general election, Democratic nominee Muriel E. Bowser has more than double the campaign bankroll of independent competitor David A. Catania, according to reports filed Tuesday with city regulators.

Bowser reported adding nearly $860,000 to her coffers since early March — a period that included the final weeks of the primary campaign, plus a post-primary stretch during which she aggressively courted supporters of other Democratic candidates.

After spending about $343,000 in that time, much of it on primary get-out-the-vote efforts, Bowser has $720,323 remaining for the general election fight.

Catania has raised just over $406,000 since March 1, reporting that sum Tuesday, plus an additional $147,000 from an exploratory campaign that was organized in December. He is left with $350,707 in his war chest.

This level of post-primary mayoral fundraising is unusual in a jurisdiction where no one who was not a Democrat has won the mayoralty in nearly 40 years of home rule.

Although Catania, an at-large member of the D.C. Council, has proved himself a formidable fundraiser in his other campaigns, persuading donors to back him against Bowser may be harder to do. Polls taken shortly before the April 1 primary showed Catania trailing Bowser in a head-to-head general election by more than 30 percentage points.

But Catania has waged an aggressive campaign in recent weeks, and his aides challenged the suggestion that fellow council member Bowser (D-Ward 4) is well ahead. Ben Young, Catania’s campaign manager, said that more than $150,000 was raised in the past two weeks and that fundraising is on pace to take in more than $1 million by fall. “We will have the financial resources to win,” he said.

Best-financed mayoral candidates have a mixed record in District elections, Young noted, citing Adrian M. Fenty’s 2010 primary loss and Linda W. Cropp’s 2006 primary loss. In this year’s primary, council member Jack Evans (D-Ward 2) raised about as much money as Bowser before the primary but finished a distant fourth.

Bowser’s campaign said about $740,000 had been raised since the primary. In a statement, Bowser said supporters from across the city “have come together to seal the deal in November.”

“Over one thousand contributors want to see our values and vision for the District in the Mayor’s office,” she said.

Since winning the Democratic nomination, Bowser has maintained a busy schedule of fundraisers and living room meet-and-greets, including a “unity fundraiser” last month attended by most of her primary opponents.

Bowser has spent almost $1.5 million since launching her campaign, including more than $300,000 on direct mail. Aides and consultants were also well paid, including the firm of strategist Tom Lindenfeld, which received $106,000. To get out the vote on primary day, Bowser’s campaign paid $100 each to more than 400 people.

Bowser and Catania will not be the only candidates on the November ballot. A Libertarian candidate, Bruce Majors, reported $1,730 in new contributions Tuesday, leaving him with $525 in his treasury.

Former Republican council member Carol Schwartz said Monday that she would pursue an independent run, but she has not registered with campaign finance officials and was not required to make a financial report. Also, the D.C. Republican Party has said it intends to nominate a candidate in the coming weeks.

Also reporting fundraising results Tuesday were candidates seeking two at-large D.C. Council seats, including the one being vacated by Catania. Four independent candidates reported each having at least $20,000 on hand for the coming months. Each hopes to win a council seat effectively set aside for a non-Democrat.

They include the Rev. Graylan S. Hagler, pastor of a Northeast Washington church, who reported raising more than $25,000, some of it from large unions that backed Hagler in a fight against Wal-Mart over the minimum wage; Robert White, a former aide to Del. Eleanor Holmes Norton (D) and the first independent to enter the race, who has built a war chest of nearly $40,000; Elissa Silverman, who finished second as a Democrat in an at-large special election last year and reported raising $26,403 since launching a campaign last month; and Khalid Pitts, a restaurateur and former union political operative, who reported more than $80,000 in receipts, including a $15,000 loan to the campaign from the candidate.

Aaron C. Davis contributed to this report.