When Gorham residents vote on building a new school to replace White Rock School, they will know exactly how much it will cost them because it will appear on the ballot for the first time next to the question.

A vote to approve the $2.5 million, 20-year bond will add 5 cents to the town’s tax rate of $16 per $1,000 of valuation, said Gorham Town Manager David Cole. The following year it will add 20 cents and drop off each year after that, Cole said.

“In year one we’re only paying interest on the bonds, and we don’t make a principal payment until year two,” Cole said.

The overall impact on the mil rate will probably stay around 20 cents, said Gorham Finance Director Dana Fischer, but he said a true number on the mil rate impact could not be calculated because through 20 years, many variable such as interest rates and the mil rates change.

“It’s really a guessing game,” Fischer said.

The referendum vote will be Tuesday, Sept. 16. Absentee ballots can be picked up at Town Hall.

Placing the cost on the ballot was the idea of Gorham Town Councilor Phil Csoros, who added language to the ballot before the Town Council tabled the bond issue in June. Csoros said voters had the right to know what the impact would be on their property taxes if the bond passes. He also said he hoped in the upcoming months to make a change to town policy so any ballot question for money appropriations would include the tax impact in the question.

“I feel it’s in the voters’ best interest,” Csoros said.

The new school is expected to cost $25.8 million, but the town will only pay $2.5 million while the state picks up the rest.

“I strongly recommend a yes vote on this referendum,” Csoros said. “This is an outstanding purchase for the town of Gorham.”

The Maine Department of Education has ranked replacing the White Rock School, which is outdated and overcrowded, 10th on a statewide priority list for help.

Built in 1962 for 85 students, the school now has 140 students enrolled in kindergarten through the second grade, and the school has had portable classrooms for more than 20 years. There are no bathrooms in the portables, forcing kids to cross the schoolyard to the main building.

The new school would be located on a piece of property owned by the town adjacent to the Narragansett School and the public safety building, known as Chick property. The property, on Main Street, is nearly 90 acres. It also has possible access to Gray Road.

Gorham wants to replace the White Rock School with a school for 550 children in kindergarten through fifth grade, giving the district three elementary schools, including Narragansett and Village schools.