Tap vs distilled water

[SarcasticDave94]

FWIW I choose to use distilled water. The well water we have is rather hard. Sediment is continually being filtered by whole house water filter and the water heater has white sediment on the bottom of the tank. Maybe calcium or lime, but not certain.

But IMO isn't it your choice what to use? Supposed best practice is use distilled but if your tap water is good it shouldn't hurt.

[Jerzasnore]

I thought the only reason to use distilled water was because it doesn't have the minerals in it that tap, well or bottled water might have... that's the only reason that I use it. Over time it was my understanding that minerals might build up in the machine if distilled water isn't used.

[Melman]

I thought the only reason to use distilled water was because it doesn't have the minerals in it that tap, well or bottled water might have...  that's the only reason that I use it.  Over time it was my understanding that minerals might build up in the machine if distilled water isn't used.

That is correct. There is no reason to use distilled water except to avoid mineral deposits in the reservoir. Using potable tap water whether from a municipal system or a well will not increase any risk of infection. Distilled water purchased at supermarkets is not sterile.  (The only commercially available sterile water is water for injection or irrigation which costs $8-20 per liter.) The use of sterile water would be pointless. You are pouring into a non-sterile humidifier and then your machine will blow non-sterile air across it (The inlet filter on your machine will not remove many bacteria and the internal components of the machine are not sterile). Also, there are environmental bacteria that will grow in distilled water. Chlorinated drinking water is more effective at inhibiting the growth of  bacteria.  Additionally, upon opening a container of sterile water it will become contaminated and bacteria will begin growing in it.


If you use tap water there is no risk of mineral deposits in the machine itself given the direction of airflow. The deposits will accumulate primarily in the the reservoir and are easily removed with a mixture of vinegar and water. If there is any aerosolization some mineral deposits may appear in the hose as well.

I am a microbiologist and have used well water for extended periods. I now use distilled water simply because I prefer it to dealing with hard water deposits in the reservoir.

[Walla Walla]

Melman, So your saying if I have no problems with my pipes and the city water is chlorinated, it's safer than distilled water?

[Crimson Nape]

Your not alone!  Famous people with Sleep Apnea:  .  .  . John Candy  .  .  .

Walla Walla, John Candy may have had sleep apnea but he died in 1994.  I think it's safe to say he's over it by now.  

[Walla Walla]

John Candy is bigger than death.

[Walla Walla]

Crimson Nape, OK all the dead guys are gone.

[Melman]

Melman, So your saying if I have no problems with my pipes and the city water is chlorinated, it's safer than distilled water?

They are equally safe. Chlorination inhibits microbial growth but the bacteria that will grow in distilled water not pathogenic and will not grow to high numbers. The only real issue is the mineral content.

EDIT: I am quite comfortable with the safety of well water which is neither chlorinated or distilled.

[Walla Walla]

Melman, Thanks! You just saved me some money.

[Melman]

At $0.87/gal switching from distilled water would not save me much. I only use a little over a gallon a  month. I prefer that to cleaning the mineral deposits from my reservoir.