Does Apple Cider Vinegar Kill Mold?

Quick Answer

Sometimes, on a hard surface, and not reliably. In the one controlled study of household vinegar against indoor molds, it stopped one common species and had no effect on the other. Apple cider vinegar is no stronger than white vinegar and can stain. For a small patch on tile, glass or sealed wood, the EPA’s advice is to scrub with detergent and water and dry the surface completely. For mold in drywall, carpet, wood or insulation, or any patch bigger than about 10 square feet, vinegar won’t fix it and the material usually has to come out.

Apple cider vinegar (ACV) is sold as a natural cure for almost everything, mold included. The claim is that its acidity kills mold on contact. The research says something more modest, and the EPA and CDC don’t recommend trying to kill mold at all. Here’s what’s actually known, what to use instead, and where the line is between a quick clean-up and a job for a professional.

What the Research Found

Very little published research tests vinegar against the molds that grow in homes. The clearest study is from 2015, when researchers at the University of South Australia tested five household and industrial agents against two molds isolated from indoor air: Aspergillus fumigatus and Penicillium chrysogenum, both common in damp buildings.

Agent tested	Penicillium chrysogenum	Aspergillus fumigatus
Vinegar (4.0 to 4.2% acetic acid)	Inhibited growth	No effect
70% ethanol (rubbing alcohol)	No effect	No effect
Tea tree oil (undiluted)	Inhibited growth	Inhibited growth
Two commercial disinfectants	Inhibited growth	Inhibited growth

Source: Rogawansamy et al., 2015 (see Sources). The study’s own conclusion was that “vinegar has limited antifungal action” and “may not be effective against the diverse fungal genera found in the indoor air environment.”

Three things to take from it:

• Vinegar worked on one of the two molds. Since you can’t tell which species is on your wall by looking, that’s a coin flip.
• It was a lab test on agar plates, not on drywall, grout or wood. The authors say testing on real building materials is still to be done.
• Vinegar leaves nothing behind. The paper notes its “lack of persistence on surfaces”, which is why mold treated with vinegar often returns within weeks.

The figure you’ll see repeated on cleaning blogs, that vinegar “kills 82% of mold species”, has no traceable study behind it. We looked, and it isn’t in the research record, so we don’t use it.

Apple Cider Vinegar vs White Vinegar

The strength of any vinegar is its acetic acid content, and in the US that is regulated. The FDA requires vinegar to contain at least 4 grams of acetic acid per 100 ml. A medical review of vinegar puts white distilled vinegar at 4% to 7% acetic acid and cider vinegar at 5% to 6%. On a grocery shelf, both are usually labeled 5%.

	Apple cider vinegar	White distilled vinegar
Made from	Fermented apple juice	Fermented diluted alcohol
Typical acetic acid	5% to 6%	4% to 7% (usually 5%)
Color	Brown, can stain grout, paint and fabric	Clear
Residue	Leaves sugars and color behind	Dries clean
Tested against indoor mold	No	Only as “vinegar” at 4% in the 2015 study
Price	Higher	Lower

So ACV is no stronger than white vinegar, costs more and can leave a brown tide mark. If you use vinegar at all, use white. Don’t waste the apple cider on walls.

One more caution: never mix vinegar with bleach. The reaction releases chlorine gas. The CDC’s rule for bleach is no more than 1 cup in 1 gallon of water, used on its own, with ventilation, and never with ammonia or any other cleaner.

What the EPA and CDC Recommend Instead

Neither agency recommends vinegar, bleach or any other chemical as a routine part of mold cleanup. Their guidance is about removing mold and fixing moisture, not killing it:

• Scrub hard surfaces with detergent and water, and dry completely. That’s the EPA’s whole instruction for a hard surface.
• Dead mold still causes reactions. EPA’s remediation guide states it “is necessary to clean up mold contamination, not just to kill the mold. Dead mold is still allergenic.” Spraying a patch and leaving it in place doesn’t make it safe.
• Porous materials may have to go. Ceiling tiles, carpet, insulation and moldy drywall can’t be scrubbed clean because the growth is inside the material. EPA’s remediation table lists wallboard as “remove and discard.”
• Fix the water first. “If you clean up the mold, but don’t fix the water problem, then, most likely, the mold problem will come back.”
• Know your limit. EPA’s guideline for doing it yourself is an area under about 10 square feet.
• You don’t need to identify the mold. The CDC says so directly, and it doesn’t recommend mold testing for homes: whatever the species, the cleanup is the same.
• Some people shouldn’t do it at all. People with asthma or mold allergies may react severely, and people with weakened immune systems or chronic lung disease can develop lung infections from mold. If that’s anyone in your household, hand the job to someone else.

How to Clean a Small Patch Safely

For a patch on tile, glass, metal, sealed wood or painted masonry that’s under about 10 square feet and has no water damage behind it:

1. Open the windows and put on gloves, goggles and an N95 mask. Disturbing mold puts spores in the air.
2. Scrub with detergent and warm water. A stiff brush or scouring pad, and some effort, removes the growth. If you want to use white vinegar as the cleaning liquid, it does no harm here; just don’t expect it to do the work on its own.
3. Wipe the surface and dry it completely. A fan or dehumidifier speeds it up. Leaving the surface damp is what brings the mold back.
4. Bag and bin anything you can’t clean. Moldy ceiling tiles, carpet underlay or cardboard go out, not back in the cupboard.
5. Find out why it was damp. Condensation on a cold wall, a dripping trap under a sink, a shower that never gets ventilated. If the patch comes back within a few weeks, the cause hasn’t been fixed. Why does my house smell musty? walks through the usual sources.

If you’d rather compare the other kitchen-cupboard options, we’ve covered baking soda and tea tree oil the same way. Short version: none of them beats detergent, water and a dry surface.

Where Vinegar Won’t Help

• Drywall, plaster and wood. Mold grows into the paper facing and the fibers, not just on the surface. Vinegar wets the surface and evaporates. See Can mold spread through drywall? for what happens behind the wall.
• Carpet, insulation and ceiling tiles. Porous, absorbent and impossible to dry evenly once soaked. EPA’s guidance is to discard them.
• Mold you can smell but can’t see. A musty smell with no visible patch usually means growth inside a wall cavity, under flooring or in ductwork.
• Mold after a leak, flood or sewage backup. The materials are wet through and need professional drying equipment, and anything touched by sewage or flood water is contaminated.
• Anything over about 10 square feet, or mold that keeps returning in the same spot.

When to Call for Help

If mold is spreading, keeps coming back, or appeared after water got in, the problem is moisture inside the building, and surface cleaners won’t reach it. We’ll connect you with trusted local mold remediation and water damage restoration professionals who can find the source, dry the structure and remove what has to go. In an emergency it’s often the fastest way to get someone out. Call us free any time, or request a free estimate.