OKLAHOMA CITY (AP) — In the last two years, Oklahoma has cited several counties for health violations at 36 water systems.

The violators in Cleveland, Canadian and Oklahoma counties range from those who operate single-well systems serving a handful of public users to municipal water utilities serving thousands, The Oklahoman reported .

Michele Welsh, the Oklahoma Department of Environmental Quality's public water supply compliance manager, said many of the systems that struggle with treatment and maximum contaminant level violations are smaller systems that serve smaller populations.

Oklahoma...