The 12,000 seat stadium was approved in the bond, which included a total of $748 million for a variety of projects including new schools.
In 2013, voters rejected a similar plan for a stadium costing nearly $70 million, but the 2014 project is now passing that price tag. However, district representatives told ABC13 that the project is not considered over budget.
The bond committee set out recommendations for how the $748 million should be spent but the school board has the authority to allocate funds differently. Cost projections change depending on a variety of factors and changes are voted on by the school board, a district representative said.
Maria Corrales DiPetta, spokeswoman for Katy ISD, said additional funds will go toward making improvements to the sports complex with a goal of making the new stadium and Rhodes Stadium next door a small-scale NRG Park.
She said the additional funding comes from surplus 2010 bond money and the general fund.
A project update on the district's website said the additional money will also go toward extra security features like a drop-off driveway loop and exterior lighting.
Parents seem torn on the issue.
Juanita Abrego said she's concerned with school crowding and the additional $12 million could have gone toward new classrooms.
"They can build more schools instead of using that money on the stadium. They can use it for schools," Abrego said.
Others, like Sue Moe, said the cost increases will pay off when Katy becomes a football destination, bringing in visitors and boosting the economy.
"It's worth it just to bring more people, just more people coming here to watch and enjoy them," she said. "It will be well worth it."