Out here in the states, distilled water is cheap and readily available - especially at refueling stations for that specific purpose.
Wow. Can I have a source on that? Normally water pumped to consumers thru pipes are chlorined in the EU to avoid germ growth - also with a lowered ph to avoid deposits. And for coolants glycol is naturally added only to avoid freezing since we can have -20° winter days up here in the nordics. Dealer and interweb told me G13 is recommended for any Prius since gen2..
Source is my neighbor via me. He is a retired chemistry prof who told me years ago that our tap water is so soft they use it as distilled water in their lab. It does have chlorine as you can sometimes smell it. But the beauty of chlorine is you just set the water out for a time and it evaporates away. We do have naturally occurring flouride so it isn't perfect.
Distilled water is defined as pure water molecules. It’s not up to your neighbor to redefine Any contaminants including chlorine or fluoride makes it by defintion not distilled. These are the other molecules or elements that will get stuck in filters or in the case of coolants, the block. It’s the boring truth of chemistry. Distilled water - Wikipedia
My neighbor is "Defining Man" and if he says it I believe it. He's more reliable than Google AI when it comes to chemistry. should have been there for our talks on alcohol . . . Wild! Ya, I'm sure there's some fluoride molecules here and there but coolant passages are huge.