IF the RO system is working properly it should be as near pure as distilled but not the bad taste of distilled.
Don't know how long you have had the RO system, but it needs to be serviced at least every 6 months, that means replacing pre-filters and sanitizing the system with bleach by-passing the membrane.
The RO system also has to be installed CORRECTLY, that means the "discharge" line which drains the bad water has to be plumbed into your sink drain correctly, it should be above the P trap and above water level, it should also go through the anti-siphon valve so there is NO chance of it sucking up sewer gases or black water from the P trap, if that happens it can contaminate the RO system and create a serious health hazard.
I had the WATTS Premiere RO system from Costco, installed it myself, it worked great and I used it for many years, they sold replacement filters at Costco for $40 bucks. You can also buy them online. They have installation and maintenance procedures also online:
Troubleshooting your system:
http://www.wattspremier.com/watts/webpa ... =28&DID=15
Milky Colored Water
This is caused by air in the system. This is a normal occurrence with the start-up of a Reverse Osmosis System. The milky look will disappear with normal use during the first 1-2 weeks. This condition can also happen after filter changes, but can usually be solved by draining the tank 1 or 2 times.
You would remove one of lines and and inject bleach into the system which pretty much kills everything.
If you have a home distiller and distill RO water you can tell how pure it is, when I did that with my RO water there was NO residual water left in the distiller tank, that indicates the water was 99.9% pure.
Water on the RO system is cloudy after installation or after servicing but it doesn't mean the water is bad.
IF the smell is coming thru your mask/hose you may need to sanitize your hose especially if a "loop" remains in the hose, water will condense at any low point or loop and start growing things. Same for humidifier tank.
While I don't believe you need to sanitize those daily weekly or monthly it is a good idea to kill any things off with bleach, bleach kills everything,
put some water in the kitchen sink put in 1/2 cup bleach and soak the hose and humidifier tank for a hour or so, then rinse really good where there is no residual smell.
You can use vinegar but I cannot stand the smell of that, like snorting a salad all night long.
Can't beat a Kenmore home distiller, distilled water for the machine, iron or anything you need distilled water for any time you need it and no running to the store burning $4.25 gallon gas.
You get NO calcium build up or water lines on the tank with distilled.
someday science will catch up to what I'm saying...