HOUSTON — Gov. Rick Perry’s decision on July 9 to refuse two key provisions of the federal health care law — the expansion of Medicaid and the creation of a state insurance exchange — is already being fiercely debated by lawmakers in Austin. But the real impact of the move will be felt far from the Texas Capitol, in the chambers of the commissioners who oversee the state’s counties.

In Texas, the burden of paying for the health care of the uninsured falls largely on county residents, whose property taxes help support so-called safety-net hospitals like Ben Taub General Hospital in Houston and University Medical Center of El Paso. Last fiscal year, taxpayers in Houston’s Harris County supplied $504 million and those in El Paso County $54 million to maintain and operate the public hospital districts that treated uninsured Texans in the two counties.

Several local leaders, health policy analysts and officials at urban hospitals across the state said Mr. Perry’s decision to reject billions of federal dollars that Texas would receive in a Medicaid expansion would hurt county taxpayers and the hospitals they support, forcing them to continue to pick up much of the tab for treatment of the uninsured.

Last year, the El Paso County Hospital District, which includes University Medical Center, asked county commissioners to raise property taxes to make up for cuts to Medicaid passed by the State Legislature and to address the growing number of uninsured patients. The commissioners, including Daniel R. Haggerty, the lone Republican, approved the tax increase, the first the county had authorized for the hospital district in 22 years. The average increase for homeowners was about $13 a year.