I like your line of thinking, except now you would need to introduce two independent clean water sources, label things appropriately, retrofit all existing plum

I like your line of thinking, except now you would need to introduce two independent clean water sources, label things appropriately, retrofit all existing plumbing, etc. also, the salt in the water would be corrosive and require totally different infrastructure. In the end, I’m not sure if it wouldn’t just be easier to make sure that all the water is potable.