Actually, I'm a bit baffled about the question. Does that mean, that in US, you have different pipings for kitchen and bathroom water? 'Cos here the water temperature is exactly the same both in the bathroom and kitchen. Or haven't your US-grynders heard of insulation&whatnot

?
Heck, here we flush the toilet with the same water we drink (no, not from the same tap, but it's the same fresh cool drinking water that flushes down our feces).