Two inmates have been diagnosed with Legionnaires' disease at Ohio's prison hospital.
State prison officials say environmental tests have been done in hopes of finding the source of illnesses at the Franklin Medical Center in Columbus.
The prison hospital houses close to 600 inmates who need medical and long-term care.
Officials earlier this week sent out an internal memo obtained by The Associated Press that advises people not to drink the tap water.
Another update sent Thursday says most of the faucets and showers now are safe to use after new filters were installed.
The bacteria that cause Legionnaires' disease usually grow in closed water systems. People can get sick if they inhale mist or vapor from contaminated systems.
