Well, if your tap water is that freakin hot then you are definately gonna be purchasing purified "drinking" water. I have accidently run overly warm water through mine but no where near the temps you mentioned. 75 degrees is prime for my
RO\DI. I also buy water because ROs are slow and they can waste a lot of water. I bought a top of the line RO\DI rated at 75 Gallons per DAY and it says the waste water should be about 4 to 1. So for every gallon of pure water you get 4 gallons of waste water. I use the waste to water house plants and stuff but I make 20 gallons of
SW every week. That means if I go all RO\DI I have 80 GALLONS of water to put some where or let it go down the drain.