More than 700 voters from Arundel, Kennebunk and Kennebunkport turned out Tuesday night for the budget validation of Regional School Unit 21.

All 18 warrants regarding the $35.7 million district budget were approved, Superintendent Andrew Dolloff said. The budget reflects a 1.9 percent increase over the current year, which ends June 30.

Dolloff said those in attendance also overwhelmingly approved a “passionate issue” — the district’s proposal to take a buyout from the district’s contract with Thornton Academy Middle School.

The buyout will cost the district about $1.2 million, but will give middle school-age students in Arundel the choice to attend either Thornton Academy Middle School or the Middle School of the Kennebunks, Dolloff said. Currently, those students are required to go to Thornton Academy by contract.

Surveys have shown more than 30 percent of Arundel parents would like their children to attend school within the district, Dolloff said. If at least eight students per grade level attend the Middle School of the Kennebunks over the next five years, the district will recover the $1.2 million and save an additional $500,000.

Voters will have final say on the buyout during a referendum vote May 24.

At that time, they will also weigh in on the district’s school budget, a referendum regarding cost sharing within the district and renovation funds for the middle and high schools.