I think that depends where you live. Regulations in my location changed so that hot had to have the same configuration as cold (and supposedly the same potability?). Old houses in the area have separate taps for hot / cold whereas newer houses built after the change have combined hot/cold.
If your water provider says it's potable I'm not going to question it, but I have yet to see a provider that makes such a claim about their hot water. It is difficult to make a statement that would apply worldwide, but where I live, it is easier to keep legionella out of cold water even if the infrastructure for hot and cold is the same.[1]
We are supplied cold water which then goes through a hot water system. My understanding was that the new configuration required the use of check-valves to prevent backflow in such a way as to reduce the risk of cross-contamination between hot/cold. I'm guessing this is now irrelevant because hot water system standards have changed to reduce risk of corrosion / infections occurring, but there is also a chance I was getting mixed up with UK regulations [0].
I don’t know why I think this, but I have it in my head that hot water heaters can have more mineral build up. This is why I always thought you should use cold water. Even though the hot was still drinkable, it might be harder water.
Yeah hot water can leach metals from the pipes that you really don't want to be drinking. This could either just taste bad, or add unhealthy amounts of lead and copper.
We are fast approaching a time when all houses have pex. At this point we've been using it in new construction for decades, and most houses with original galvanized pipes are either already replaced with pex, or getting really close.
Sometimes houses with water softeners will run non-softened water to the cold tap on the kitchen sink for cooking purposes, as some people don't want the salted water.
