Posing as homeowners, investigators nabbed 111 unlicensed contractors, including 11 in Riverside County, this week.
The California State License Board conducted a two-day, statewide sting in seven counties during what has been dubbed the annual "California Blitz."
Undercover investigators invited suspected unlicensed contractors to bid on various constructions jobs, from plumbing and flooring to roofing.
Riverside County’s District Attorney Paul Zellerbach said he was satisfied with the results.
"First and foremost, you get shoddy work done," he said of the sting's targets. "Second off, most of these unlicensed contractors will quit halfway through the job."
High unemployment means more unlicensed contractors, and while some are just trying to make a living, others are more questionable, according to Rich Lopes, of the Contractor State License Board.
"We caught four different people who actually had arrest warrants against them, we caught two registered sex offenders," Lopes said.
Homeowners can protect themselves by asking potential contractors for a license number, which is required in California for any job costing more than $500.
Behavior could also be a key into weeding out unlicensed contractors.
"You’re only supposed to pay 10 percent of the price up front," Zellerbach said. "If they ask more than that, it’s suspicious. Don’t do it."