His three-round total of 22-under-par is one stroke off of the Nationwide Tour record. David Branshaw set the record of 23-under-par 190 at the 2002 Gila River Classic.
Steve Allan (68) and Ken Duke (68) are tied for second at 20-under-par 196. Mike Grob carded a 5-under 67 Saturday to climb into fourth place at 17- under-par 199.
Wetterich, who needed just 24 putts to complete his third round, began the day three strokes behind overnight leader Wes Short and got off to a quick start.
He rolled in an eagle putt from 12 feet at the par-5 first. This eagle got Wetterich rolling on the par-5s, which he went 5-under-par on the five par-5s.
The 29-year-old erased his early three-shot deficit with a birdie at the par-3 third. He continued his roll with birdies at Nos. 5 and 7, both par-5s.
Around the turn, Wetterich again attacked a par-5 when he two-putted for birdie at the 12th. He was unable to take advantage of the final par-5, No. 14, but did roll in a 15-foot birdie at the next. His birdie from 12 feet out at the par-4 17th gave him a two-stroke advantage on the field.
'I hit the ball really solid today,' said Wetterich. 'I started off with an eagle and took off from there.'
Wetterich was able to card the low round of the day despite battling winds of up 30 m.p.h.
'It was more about hitting it in the direction you wanted and not letting the wind throw it around,' said Wetterich. 'To be honest, I just wanted to get in, two pars would have been nice, so to get a birdie was a bonus.'
Allan and Duke each had five birdies and one bogey in their rounds.
Allan had three birdies and a bogey on the front nine, then two birdies on the back side. Three of his birdies came on pars-fives, with all three coming after he chipped within two feet of the hole.
'The saving grace was three of the par-fives were downwind,' said Allan. 'You have to control it a lot better.'
Duke was just the opposite of Allan with two birdies on the front and three birdies and a bogey on the back. However Duke, like Allan, birdied three of the par-fives.
'I am satisfied with my round,' said Duke. 'The conditions were tough. I was just trying to keep warm.'
Short faltered with a round of one-over 73 to drop into a fifth-place tie at 16-under-par 200 alongside Robin Freeman, who shot a 68 Saturday. Tom Carter (72) and Russ Cochran (66) were one stroke further back at minus-15.