Be very careful about inhaling steam in the bathroom.
So many people have turned down the temperature on their water heaters to save on energy, that it can be very dangerous because the water is not hot enough to kill various bacteria. For instance, Legionellosis can occurred when individuals inhale aerosols contaminated with the bacteria, but evidentally doesn't happen if the water is super HOT-hot in the water heater.
And there is a recent news article about a DANGEROUS bacteria which is a "cousin" of tuberculosis being found in many people who have serious sinus infections.
Here's the url to the news article:
The germ is called atypical mycobacterium, a first cousin of the tuberculosis germ, which isn't killed by the chlorine used for tap water by water treatment plants. They advise people to only use sterile water for nasal rinsing.
I've read online that ONLY distilled water is free from ALL bacteria, so MAYBE boiling tap water is not enough to ensure it is safe for nasal rinses. I don't know, I haven't researched this enough yet....