Almost two months since it landed on Gov. Mark Sanford’s desk, a bill aimed at providing property tax relief has hit a snag.

Sanford won’t say why he has not signed the bill, which would prevent local governments from raising property values for tax purposes more than 20 percent during reassessments.

But those familiar with the issue say Sanford likely is weighing a threatened lawsuit, opposition by the state’s most powerful business lobby, and potential constitutional problems.

His delay has counties that reassessed property recently fretting about which tax values they should use on their bills. Richland County decided Wednesday to delay its reassessment until next year.

Supporters of the measure want Sanford to take action.

“I wish he would go ahead and sign it,” said Rep. John Graham Altman, R-Charleston, a co-sponsor of the bill. “We’ve got to do something to control runaway taxes.”

Others are glad for the wait.

“I have some significant concerns about the bill,” said House Minority Leader James Smith, D-Richland, who initially was a co-sponsor but raised questions about it later. “I appreciate the in-depth time they’re taking to look at it.”

Supporters like the bill because it offers a cushion for homeowners whose property values skyrocket every time counties reassess tax values.

But opponents — including the S.C. Association of Counties, the S.C. Chamber of Commerce and advocates for the poor — say it could violate the state constitution, one of several grounds on which a taxpayer could challenge in court.

Opponents say a cap on reassessment values would shift the burden to taxpayers whose property doesn’t increase as much.

That means most businesses and many low-income homeowners would pay more than their share.

“Suing is certainly an option,” said Hunter Howard, president and chief executive officer of the state chamber.

Howard is working with the Association of Counties to gather information about how local governments would be harmed by a cap. He hopes to present the report to Sanford — and make it public — in about a month.

He and others also argue counties will be forced to raise taxes to make up for the lost revenue.

Richland County assessor John Cloyd has criticized the cap, saying it would not address the larger problem of how to pay for school operations and buildings.

“Whatever Band-Aid application you put on it,” he said, “it will just wear out in a year or two or three.”

For example, Howard said, a cap in Beaufort County would force a $50 million tax shift mostly to businesses and homeowners who live on less desirable property farther from the beach.

“This is not going to be pleasant unless you live on the water,” Association of Counties lobbyist Robert Croom said.

Opponents also say state senators voted improperly on the bill, which was tacked onto another measure in the last days of the session. They argue that because it gives a tax exemption, a two-thirds vote was required for passage.

It only received a voice vote, so no record was made of who supported it.

Rep. Vida Miller, D-Georgetown, the bill’s chief sponsor, wishes Sanford would sign it so the lawsuits would be filed and the courts could decide the issue.

“We found that there is a rallying cry around the state for some type of property tax relief,” Miller said.

The court decision, she said, “would give us some direction” on how to provide that relief.

“This isn’t perfect, but it is the beginning of what could be some meaningful dialogue,” she said. “And the only way we’re going to get that dialogue is if the governor would go ahead and sign this bill.”

Reach Talhelm at (803) 771-8339 or jtalhelm@thestate.com Staff Writer Shelley Hill contributed to this report.