Hellewell, an Orem Republican, announced Friday that he will not run for re-election, opening the door for state Rep. Margaret Dayton, R-Orem, to take the seat.

But Hellewell said he was not scared off by the intraparty challenger.

"Beating her would have been the least of my worries," Hellewell said.

Dayton is slated to announce her official Senate candidacy this week.

Hellewell said his business, PPM Inc., which provides plumbing, heating and air conditioning service, is growing quickly and demanding more attention.

"It was too much," he said. "It came down to either doing two jobs mediocre or do one good."

He recently bought out three competitors and plans to move into a larger building and expand his operations from Utah County into Salt Lake County and Park City.

Even with his business success, Hellewell said, bowing out of the race "was probably one of the hardest decisions I have made in my whole life."

He was first elected to the Senate in 1999 and made a bid for the governorship in 2004. He said he enjoys public service and hasn't ruled out a comeback in a few years.

During his final legislative session, which began Monday, Hellewell plans to run legislation aimed at cleaning up the state's election code and making it easier for people to obtain a provisional ballot when the person's identity or right to vote is challenged.

mcanham@sltrib.com