How often should you clean a humidifier?

The EPA advises emptying and drying a portable humidifier daily and disinfecting it every third day. That is more often than most owners expect, but standing water at room temperature grows bacteria and mold within a few days, and an ultrasonic or impeller unit will then aerosolize that growth into the room air. Rinse and dry the tank every morning, and do a full descale-and-disinfect on the EPA's roughly every-third-day schedule or at least weekly. Change the water daily rather than topping it off.

What do you use to clean a humidifier?

White vinegar to descale the mineral buildup, and a diluted disinfectant to kill germs. Fill or wipe the affected parts with undiluted or lightly diluted white vinegar, let it sit 20 to 30 minutes to dissolve the chalky scale, and scrub with a soft brush. For disinfecting, use the solution your manufacturer specifies — commonly a dilute bleach solution (about a teaspoon per gallon) or 3 percent hydrogen peroxide — then rinse thoroughly so no chemical residue gets aerosolized. Never mix bleach and vinegar; the combination releases toxic chlorine gas.

How do you get mineral buildup out of a humidifier?

Descale it with white vinegar. Empty the unit, pour vinegar into the base and tank over the scaled areas, and let it soak 20 to 30 minutes so the acid dissolves the calcium and magnesium deposits. Then scrub with a soft brush or an old toothbrush for tight spots, and rinse. Heavy, hardened scale may need a second soak. Using distilled water instead of tap water going forward dramatically slows how fast the scale comes back, especially in hard-water areas.

Can a dirty humidifier make you sick?

Yes. A humidifier that isn't cleaned grows bacteria and mold in the standing water, and ultrasonic and impeller units then spray those microbes into the air along with the mist, where they can be inhaled. The EPA specifically warns that dirty humidifiers can cause breathing problems and can worsen asthma and allergies. This is the whole reason for the frequent cleaning schedule. Warm-mist units are less prone to spreading microbes because they boil the water, but they still need descaling and cleaning.

Is it better to use distilled or tap water in a humidifier?

Distilled or demineralized water is better, especially for ultrasonic and impeller units, because it contains almost no dissolved minerals — so it produces far less scale inside the machine and no white mineral dust settling on your furniture. Tap water is acceptable in evaporative and warm-mist units, which leave the minerals behind in the wick or boiling chamber rather than aerosolizing them. Whatever water you use, cleaning the unit on schedule matters more for health than the water type, because microbes colonize the surfaces, not the water.

How to Clean a Humidifier (Descale and Disinfect, EPA Steps)

Written & researched by Derek Holt Home & Appliances Editor

Updated August 2026

Overhead view of a person adjusting a floor-standing air purifier in a quiet living room, in warm late-afternoon light

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Cleaning a humidifier is a five-minute job you should do far more often than you probably do — the EPA recommends emptying and drying it daily and disinfecting every third day. It costs nothing but white vinegar and a little disinfectant, and there’s no risk beyond ordinary chemical care. This isn’t about appearances: an uncleaned humidifier grows bacteria and mold in its standing water, and an ultrasonic unit sprays that straight into the air you breathe. The two rules are descale the mineral scale with vinegar and disinfect the tank — and never mix bleach and vinegar.

The Best Way to Clean Your Humidifier (Clean That Up)

Tools and materials

White vinegar for descaling and a manufacturer-approved disinfectant (dilute bleach or 3 percent hydrogen peroxide) for germs.
A soft brush or old toothbrush for tight corners, plus a soft cloth and clean water for rinsing.
Distilled water for refilling if you have hard water — it slows scale dramatically. See our best humidifier picks for models that resist buildup.

Close-up detail of the material being worked in a air quality project, in soft overcast light

Step 1: Unplug and disassemble

Switch off and unplug the humidifier — never clean a plugged-in unit. Empty any remaining water, and take it apart as far as the manual allows: remove the tank, the base, and any wick, filter, or nozzle. Set aside the wick or filter, which usually gets rinsed or replaced rather than soaked in vinegar.

Step 2: Descale with vinegar

Pour white vinegar into the base and tank over the chalky mineral deposits, or fill the tank with a vinegar-water mix, and let it soak 20 to 30 minutes. The acid dissolves the calcium and magnesium scale that builds up on the transducer, heating element, or tank walls. Scrub the loosened deposits with a soft brush; give heavy scale a second soak if needed.

Overhead view of a person adjusting a floor-standing air purifier in a quiet living room, in warm evening lamplight

Step 3: Disinfect the tank

After descaling, disinfect with the solution your manufacturer specifies — commonly about a teaspoon of bleach per gallon of water, or 3 percent hydrogen peroxide. Swish it through the tank and base and let it sit the recommended time to kill bacteria and mold. Critically, do this as a separate step from the vinegar and rinse in between — mixing bleach with vinegar releases toxic chlorine gas.

Step 4: Rinse thoroughly and dry

Rinse every part several times with clean water until you can’t smell vinegar or disinfectant — any residue can be aerosolized into the room. Wipe or air-dry all surfaces completely. Drying matters: a humidifier put away damp grows the very microbes you just killed. Let the parts dry fully before reassembling or storing.

Low-angle view of a person adjusting a floor-standing air purifier in a quiet living room, in warm late-afternoon light

Step 5: Maintain the schedule

Going forward, empty and dry the tank daily rather than topping off old water, and disinfect on the EPA’s every-third-day cadence (weekly at minimum). Use distilled water to slow scale, and replace wicks and filters on the manufacturer’s schedule. This routine is what keeps the mist clean instead of spreading mold and bacteria into your air.

Where to go next

Humidifier care sits alongside cleaning a dehumidifier and replacing an air purifier filter as core air-quality maintenance. If tap water is your issue, see whether tap water is safe in a humidifier. It all lives under the air quality hub.

We never buy or physically test the products we rank — our picks come from aggregated owner reviews and expert consensus, explained on how we rank. Follow your unit’s manual for its specific cleaning products.

How to Clean a Humidifier