AUSTIN (KXAN) — Tuesday is Election Day, and Austin voters will decide on several local races, with 28 candidates vying for five council seats and six mayoral candidates on the ballot.

With a larger pool of candidates comes the possibility of a runoff election. But what triggers a runoff, and when would that be held in Travis County?

A runoff election happens when no single candidate earns more than 50% of the vote. When that happens, the two candidates with the highest percentage of votes will compete in a runoff election.

This year’s runoff election, if needed, will be held on Tuesday, Dec. 13, with an early voting period between Dec. 1-9.

The complexities with runoffs aren’t just another election for candidates to get through, but an additional month of campaigning, said Brian Smith, a political science professor at St. Edward’s University. Many candidates will spend all their money raised by Election Day, making late-stage coalition building trickier, he said.

“You then have to decide, ‘do I have enough votes to make it competitive for the Dec. 13 runoff? Or do I want to drop out,'” he said, adding: “A lot of times candidates spend to that last dollar on Election Day, realize they made it to a runoff, and now they have no resources.”

The last time Austin voters saw a runoff election was in December 2020, which featured two Austin City Council district races and two Austin ISD trustee positions. Then-council incumbents Jimmy Flannigan and Alison Alter ran against challengers Mackenzie Kelly and Jennifer Virden to represent districts 6 and 10. Alter maintained her council seat while Kelly secured the majority of runoff votes.

In that election runoff, there were more than 562,000 registered voters who were eligible to vote. In total, only 54,700 — or 9.73% — of those eligible voters cast a ballot.

With district runoffs, only registered voters living in those runoff races can cast a ballot. Still, Smith said December runoffs traditionally see much lower turnout than spring runoffs, which feature state-level partisan races.

Those state-level partisan races extending from primary elections traditionally generate a lot more buzz and voter interest, Smith said. With only local, nonpartisan races on the December runoff ballots, that often translates to lower voter interest.

“It’s all going to be local, and that means a lot lower turnout,” he said. “So because of that, the candidates who are in the runoff have to really mobilize their base to come out, because there’s not going to be, really, those pull factors to get them out to the polls.”