The solitary came from veterans Stu Gillespie and Rick Harding with a 3 and 2 victory.
Wanganui needed four points to gain promotion and did it in a canter.
Gillespie won 6/4, Harding won 4/3, Hooper won 3/2, Nicholson won 2/1, while Hulme halved his match. Smith lost 1 down.
The final points tally was Wanganui 5 and-a-half, Levin 3 and-a-half.
"We need five points to get promoted and we got their in the end," Gillespie, the team's spokesman said.
"We're just very thankful for all those players who made themselves available throughout the season," he said.
As well as the six playing on Sunday, contributions had earlier come from Caleb Tuck, Keith Johnson and Riki Kauika.