Harriman architects of Auburn has designed a school for 1,050 elementary and middle school students from Mexico and Rumford. The site in Mexico is where Meroby Elementary and Mountain Valley Middle schools currently stand. Lincoln Brown Illustrations

RUMFORD — Voters in the seven towns of Regional School Unit 10 must decide again on building a $91.8 million school in Mexico, because Mexico’s warrant was posted June 8, one day short of the legally required minimum of seven-day notice.

The first vote on June 14 was 938-591 in favor of the project.

The second vote will be Election Day, Nov. 8.

Superintendent Deb Alden announced the decision at the board of directors meeting Monday at Mountain Valley High School in Rumford. The error was discovered by the district’s attorney on Sept. 22 while drafting documents for the new school building to bring to lending institutions. She and Business Manager Leah Kaulback and the attorney researched possible alternatives to another vote, but none have been found, she said.

Because Rumford, Mexico, Hanover, Roxbury, Buckfield, Hartford and Sumner are members of the district, legally residents of all the towns must vote as an entity, even though voting is held in each town, Alden said.

A public hearing on the project is set for 6 p.m. Oct. 24 at Mountain Valley High School. Warrants giving notice of the Nov. 8 vote are scheduled to be posted in all seven towns no later than Nov. 1.

The school is planned for the site of Mountain Valley Middle School at 58 Highland Terrace and Meroby Elementary School at 21 Cross St., both in Mexico. It would replace those schools and Rumford Elementary School and serve students in prekindergarten through eighth grade.

It would accommodate up to 1,050 students and serve children with disabilities from birth to 5 years old. Plans include a health clinic in partnership with Rumford Hospital and an early childhood education program run by Region 9 School of Technology staff and students.

About 98% of the cost would be paid by the Maine Department of Education in subsidized bonds.

The district is “hoping that by next year at this time for the construction to begin,” Alden said in an email Tuesday. Harriman, the architect for the building, is working on fine-tuning the detailed blueprints for approval from the Department of Education, she said.