Maricopa County Sheriff Paul Penzone is warning that private prisons pose a financial threat to county jails, by leaving the jails with inmates who cost the most money to house.

Penzone's comments on this weekend's "Sunday Square Off" come as the City of Mesa weighs whether to become the first city in the state to hire a private prison operator.

Until now, the debate over the cost of private prisons versus taxpayer-owned prisons had been going on only at the Capitol.

Mesa would send misdemeanor offenders to a private prison, while more serious offenders would still go to Penzone's jails.

Penzone said he's working with Mesa on a deal to reduce jail costs. He warned that the county would be a net loser by being stuck with higher-cost inmates.

Private prisons are "going to be taking those that are least expensive to themselves - they don't have medical expenses or mental illness, they're not highly violent," Penzone said.

"The ones that cost the most to house are still going to be our burden, where they reap the benefit of taking those that are least expensive."

Two-thirds of the Maricopa County Sheriff's Office budget is dedicated to jail operations.

Penzone also discussed:

-Whether he had any second thoughts about shutting down Tent City

-Why MCSO won't remove ICE agents from its jails

-Whether Joe Arpaio's pink underwear for inmates is on its way out

Also on this weekend's "Square Off":

-I ask GOP State Sen. Debbie Lesko whether she'd support a larger increase in teacher pay from the projected savings in her just-passed school voucher expansion.

Will lawmaker back teacher raises with savings from vouchers?

-Michel Marizco, editor of KJZZ's Fronteras Desk, says drones and other technology will play a large role on Arizona's border as President Trump's wall goes up.

Why Arizona border wall will rely on tech more than cement

"Sunday Square Off" airs at 8 a.m. Sundays on 12 News, after "Meet the Press."