I think the point is that a cold water line is easily flushed before use, and it's less likely to breed or incubate biologics. I wouldn't call water standing i

I think the point is that a cold water line is easily flushed before use, and it's less likely to breed or incubate biologics. I wouldn't call water standing in accumulated scale and sediment "clean" any more than I'd prefer to drink from a stagnant pool than a stream!