"Watford came in at the weekend and made an enquiry," Levein told the Scottish Sun.
"It's a big job, but I wasn't the slightest bit interested.
"No disrespect to Watford, but I won't be leaving United unless I get the boot or something really attractive comes up."
"I'm still a hugely ambitious person and want to manage at the top level," he added.
"But I like it here and I'm happy, which is a big thing for me."