Wadkins posted a 1-under 71 after a three-putt bogey at the last to end at 11-under-par 205. He was joined there by Lonnie Nielsen, who shot a bogey-free, 4-under 68 thanks to three birdies on the back nine.
Tom Jenkins, who briefly shared the lead on the back nine, bogeyed his final two holes to card a 2-under 70. He shares fourth place at 8-under-par 208 with Tom Kite, who also shot 70 in round three.
Wadkins, who won the Senior Players Championship earlier this year, got on the board with a birdie on the third. Another birdie at the par-5 sixth at Reserve Vineyards & Golf Club moved Wadkins to 12 under, four clear of Nielsen.
Things quickly began to change at the ninth. Wadkins' second shot went left of the greenside bleachers. He got a free drop from the bleachers, but still could not save par.
Wadkins also bogeyed the 10th to slip to minus-10. As he parred the next four holes, Jenkins got into the fray.
Jenkins opened with birdies on one and three. He gave a stroke back with a bogey on No. 5, then parred his next six holes. Jenkins ran off three birdies in a four-hole span from the 12th to grab a share of the lead at 10 under. His late struggles cost him though.
Nielsen was right there as well. After four pars to open his round, Nielsen birdied the fifth from 12 feet out. He carded his next birdie at 12 to move to minus-9.
Wadkins hit a stellar bunker shot to 5 feet from short of the 15th green. He rolled that putt in, but Nielsen also birdied the hole to remain one back as he got up and down from a greenside bunker.
A two-putt birdie on the 16th moved Wadkins to 12 under, but his lead was still only one as Nielsen also two-putted for birdie.
At the last, Wadkins left himself 35 feet for birdie. However, he left his birdie try seven feet short and was unable to sink the par putt to fall back to 11 under.
'I played halfway decent, but didn't make the putts when I needed to,' stated Wadkins. 'I left some putts short. I don't like finishing with a bogey like I did today.'
Nielsen hit his drive at 18 into the trees on the right, then pitched out. He dropped his third on the green, but had over 47 feet for birdie. Nielsen two-putted for par to earn his share of the lead thanks to a bogey-free round.
'The key to the round has been to stay away from bogeys this week,' said Nielsen, who has just two bogeys over the opening 54 holes. 'The birdie on 15 was a nice confidence builder.'
Nielsen had a chance to take the Senior Players Championship that Wadkins won, but a bad final round doomed Nielsen.
'I had a chance to win at the Senior Players this year and didn't get it done,' Nielsen admitted, who shot 4-over 76 in the final round. 'It was my most disappointing round this year. It would mean a lot to me to play well tomorrow.'
David Edwards moved into a share of sixth place at 7-under-par 209 thanks to a 5-under 67. He stands alongside Larry Nelson (70) and Tom Purtzer (71). Keith Fergus, Bruce Fleisher, Bob Gilder, Morris Hatalsky, John Jacobs and Eduardo Romero are one stroke further back at minus-6.