I’ll give you that caveat. My brother lives in the rural town where we grew up in the butthole of Oklahoma, and his water is so hard that they justified spending thousands of dollars on a whole home water softening system. My in laws pump their own water and it’s foul. I think they need to be filtering it. I think there’s something in their groundwater.
As for the water in the urban and suburban parts of Oklahoma City, it’s pretty hard to find truly bad tap water.