That's the type of assumption that caused this disaster, that a treatment plant is a treatment plant is a treatment plant. A lot of professionals, even, prior to Flint, would have thought along the same lines - just fire it up, adjust the coagulant dose, make sure the microbiological samples come back clean, and you're good to go. There's also a long history among environmental agency drinking water staff of dragging out lead and copper violations. Oh, it's probably just old fixtures, change them out and let's wait 6 months and then sample again. Of course, the local drinking water professionals - both utility and regulator - should have known of the risks posed by the lead service lines still in service. But regulators in the state office might not have, and frankly were probably less experienced overall with actual, real-world water systems. I can tell you one thing, a failure to consider water chemistry is a lot less likely now, and everyone in the industry now is a hell of a lot more aware of this issue now.