BROKEN ARROW, Oklahoma - A religious freedom group is threatening to sue the City of Broken Arrow because the First Baptist Church's name is on a water tower.

The water tower was painted at least ten years ago, and the name is up there because the city needed church property for a water tower.

First Baptist gave up the land in exchange for the name. It wasn't controversial until recently when a citizen complained it must be unconstitutional.

City Attorney Beth Ann Wilkening said it isn't, it was simply part of a land deal.

“Agreeing to put the name ‘First Baptist Church’ on the tower in exchange for the land for the water tower, the easement ad and I think some right of way,” she said.

Now the deal could lead to a lawsuit.

The Freedom from Religion Foundation sent a letter to Broken Arrow asking them to paint over the sign.

"It's a city endorsing one particular church over others and endorsing one religion over another," said attorney Andrew Seidel.

And while Broken Arrow maintains the arrangement was merely payment for the land, Seidel said, “Government cannot contract their way out of their constitutional obligations."

The city council turned down the outside request to paint over the sign, and the city attorney said the city can defend their stance in court.

“It wasn't intended to endorse any sort of religion; it was simply to recognize them for the land contribution. It was a contract,” Wilkening said.

The Freedom from Religion Foundation said if they're not able to convince Broken Arrow to change the sign they're willing to file a lawsuit; and, they said, they've won similar lawsuits before.