— Town Council voted unanimously Wednesday to change the town’s election from a winner-take-all format to one where the winner would need at least 50 percent of the vote.

Council appears certain to give final approval to the change on Aug. 13, two days before filing opens for the mayor and four Town Council seats.

“We have one more reading,” Councilman Chris Nickels said. “It will pass unanimously again.”

The change comes after Mayor Billy Swails surprised town officials by announcing that he will not seek a second four-year term this fall. He had attracted only one challenger, former Councilman Joe Bustos, but now the race could include several more.

Swails abstained from the vote, and Councilwoman Linda Page was out of town.

Page, Councilman Ken Glasson, former Councilman Paul Gawrych and lawyer Waring Howe are among those considering a mayoral run.

The city of Charleston also has a system where if no mayoral or council candidate receives at least 50 percent of the vote during the initial election, the top two vote-getters face off in a runoff.

Council members also agreed to make the change apply to their own elections, which the town attorney had advised. Nickels said there would not have been a runoff two years ago, when about eight candidates sought one of four at-large seats.

However, he said if there are many more candidates seeking four seats — such as the 19 hopefuls who ran in 2009 — then a runoff would be held among the top five vote getters.

Reach Robert Behre at 937-5771.