A sleep medicine doctor prescribed me an ASV (adaptive servo ventilation) machine that must use DISTILLED water. Airports sell bottled water with natural minerals, NOT distilled water. Do I need a prescription to bring distilled water?
I fly for work, usually to European Union, British Isles, Asia, Middle East (mostly Abu Dhabi, Bahrain, Doha, Dubai, Israel) , North America.
My distilled water was thrown away.
Don't bother trying to get distilled water through security.
It always takes me a couple of days to find a decent grocery store when traveling so you need a plan to hold you over for a few days while you acquire distilled water.
According to my MD, the biggest risk in using non-distilled water is the bacteria that causes Legionnaires' disease. Who knows? Some water supplies contain this bacteria (and others). Breathing bacteria water is not so groovy.
Based on my experience, tap water that is high in mineral content will add scale to your CPAP's water chamber. Tap water from areas using ground water contaminated by industrial activity (like anywhere in Texas where they are pumping crude oil) fouls the air you breath. Tastes bad (rotten eggs)! Yuck. Chicago tap water is often this bad. It isn't just Texas.
This leaves bottled water. According to Consumer Reports, bottled water is often no better than tap water. Depends on brand and bottling plant.
Desani bottled water is my first choice. Available at fine McDonalds everywhere.
Second choice Aquafina then Ozarka. My choice isn't particularly scientific. These seem to be the most consistent in terms of taste, clarity, and availability.
If you want to get scared about bottled water quality go to http://www.nrdc.org/water/drinking/bw/bwinx.asp
Some hints about making your trip through airport security a bit more efficient. You have to run your CPAP through the xray machine. The TSA will want to check it for bomb residue. If you have it enclosed inside of a suitcase or roller bag, TSA will have to swab the CPAP and the bag and the stuff inside the bag. Basically, your bag gets searched.
I've started treating my CPAP like a laptop. I take it out of the bag. I don't take out the hose, face mask, or power cord. Now, I'm not keen on having my breathing machine exposed to the germ infested environment of xray buckets, inspection tables, etc. To solve that little problem, I have a drawstring closing bag (small version of a sleeping bag stuff bag). Then my CPAP is protected from prying eyes and germs. Gets me through security faster. they just swab the CPAP a couple of times, stick the cloth thing in the machine and I'm on my way. Everyone is happy.
One other thing. TSA seems to be getting used to CPAP machines. While they don't know necessarily what they are used for, they are not surprised to see them. As soon as I've been assigned a secondary screener, I tell them it is a CPAP machine. They probably already know that but I get some small comfort in stating the obvious anyway.