Trewavas was returned for a fourth term, with a preliminary result of 5215 votes, after 90 per cent had been counted.
"It's an honour to be selected to once again represent our beautiful district," he said.
"I'm looking forward to carrying on all the great work that we have under way and to keep working to make this a fantastic place to live for all our community."
Trewavas said there were positive signs ahead for the region's main industries such as forestry, farming and energy. Even the important tourism industry was bouncing back strongly from Covid-19.
The other two mayoral candidates, Christine Rankin and Sean Wakelin, achieved 3782 and 926 votes respectively in the interim results.
Rankin also challenged for the mayoralty three years ago and was given the job of deputy mayor in the last term.
It has been a friendly rivalry but Trewavas said he would not be making a decision on his deputy until he had met the new team of councillors, which includes five new faces.
"We will just see who is the best fit for the job. Christine has been a good deputy but we will assign that in the coming weeks, probably November."
The seven successful candidates for the Taupō ward are: Christine Rankin, Yvonne Westerman, Kevin Taylor, Anna Park, John Williamson, Rachel Shepherd and Duncan Campbell.
The successful candidate for the Tūrangi-Tongariro ward is Sandra Greenslade.
In the new Te Papamārearea Māori ward, Karam Fletcher and Danny Aperahama Loughlin were the successful candidates.
Kylie Leonard for the Taupō East Rural ward and Kirsty Trueman for the Mangakino-Pouakani ward were both re-elected unopposed.
The newcomers are Shepherd, Campbell, Greenslade, Fletcher and Aperahama.
All of the sitting councillors who decided to run again were re-elected.
Trewavaas said the most challenging issue of the past three years was the traffic reconfiguration in the town centre, which had not been popular with all permanent residents.
The four-lane road through town has been reduced to two lanes, with through traffic redirected down Spa Rd and Titiraupenga St, creating a more pedestrian and shopper-friendly environment and linking the CBD with the lakefront.
"I acknowledge there is a bit of pain in the change but I'm sure the final outcome will be good for everyone."