Marietta High is the only high school in Cobb County without an auditorium.
The cost to taxpayers depends on whether voters approve the SPLOST IV in a 2013 referendum, as the sales tax revenue would be used to pay off the auditorium debt.
If the SPLOST IV fails, owners of homes valued at $200,000 will face a tax increase of about $11 a year to pay off the bond, starting in 2015.
Those who voted in favor of the school bond and new auditorium pointed to their support of Marietta City Schools.
"I came out for Marietta High School," Ronald said before voting at Marietta Middle School Tuesday. "Marietta city has always been a strong supporter of education and preparing our children."
"I have two small children who will be in there (Marietta High School)," a Marietta woman said. "I'm willing to take a tax increase for the auditorium."
Those against the Marietta school bond said the new auditorium is unnecessary and costly.
"If they wanted one, they should have done it when they built the school," a woman said after voting at Marietta Middle School Tuesday morning.
"We already have enough other facilities in Marietta," Pam Wood said Tuesday.