What kills mold? Bleach, vinegar, peroxide and detergent compared

Why is “what kills mold” the wrong question?

Because killing mold does not finish the job. EPA says plainly: “Dead mold may still cause allergic reactions in some people, so it is not enough to simply kill the mold, it must also be removed.”

That changes how you judge any product. The question is not which liquid kills the most mold. It is which method gets the growth off the surface, and whether the material can be cleaned at all.

EPA’s household method uses no special chemical. “Scrub mold off hard surfaces with detergent and water, and dry completely.” Porous materials such as ceiling tiles and carpet “may have to be thrown away,” EPA says, because mold grows into their crevices and may be impossible to remove completely. No spray changes that.

EPA also notes that it is “not possible or desirable to sterilize an area.” Some mold spores will always be in indoor air and dust. They will not grow if the moisture problem is fixed. That is why every authority puts drying and leak repair ahead of any product. For the full DIY process, see how to get rid of mold. For background on identification, health and cost, see the mold hub.

How do the common options compare?

This table summarizes what EPA, CDC and the limited published research say. It does not rank products by kill rate, because no agency publishes one for household use.

Does bleach kill mold, and should you use it?

Chlorine bleach is a biocide, which EPA defines as a substance that can destroy living organisms. But EPA’s position is clear: using a biocide “is not recommended as a routine practice during mold cleanup.” EPA allows that professional judgment may call for one, for example when people with weakened immune systems are present.

If you decide to use bleach, follow CDC’s limits:

• Use no more than 1 cup of household bleach in 1 gallon of water.
• Never mix bleach with ammonia or any other cleanser.
• Wear gloves made of natural rubber, neoprene, nitrile, polyurethane or PVC (EPA).
• Ventilate the area and exhaust the air to the outdoors (EPA).

Scrub first, then apply the diluted solution if you want a disinfecting step, then let the surface dry. Using bleach in place of scrubbing leaves dead mold behind.

Bleach is a poor fit on porous materials. EPA’s guidance for drywall, ceiling tiles, insulation and carpet with mold growth is removal, not treatment. Stronger bleach is not more effective in any guidance we found, and it raises the fume risk.

Does vinegar kill mold?

The evidence is thin. EPA and CDC household mold guidance does not mention vinegar at all.

The most direct published test we found is a 2015 laboratory study in the International Journal of Environmental Research and Public Health by Rogawansamy and colleagues. They tested household vinegar (about 4 percent acetic acid) against two molds collected from indoor and outdoor air. Vinegar inhibited Penicillium chrysogenum but had no effect on Aspergillus fumigatus. The authors concluded that vinegar “may not be effective against the diverse fungal genera” found indoors. The test was done on lab plates, not on walls or tile, so it says nothing about real surfaces.

Vinegar is mildly acidic, cheap and familiar, which is why it shows up on so many cleaning lists. If you use it on a light film of mildew on glass or tile, scrub the growth off and dry the surface, just as you would with detergent.

Never use vinegar and bleach together or one right after the other on the same surface. CDC’s rule is to never mix bleach with any other cleanser.

Does hydrogen peroxide kill mold?

We could not find EPA or CDC household mold guidance that recommends hydrogen peroxide. We also did not find a primary source that gives a household concentration or contact time for mold. So we do not publish one.

What we can say with confidence comes from EPA’s pesticide rules. A product that claims to kill, prevent or mitigate a pest, which includes mold and mildew, is a pesticide under federal law and generally must be registered with EPA before it can be sold. Registered products show an EPA registration number on the label, along with directions for use.

If you want a peroxide-based product, choose one that lists mold or mildew on an EPA-registered label and follow that label exactly. Scrub the growth off either way. Do not combine peroxide with vinegar, bleach or other cleaners.

What about Concrobium and other mold sprays?

Commercial mold sprays fall under the same EPA pesticide rules. Concrobium Mold Control, one of the most searched brands, is registered as EPA Reg. No. 82552-1. Its label lists 0.95 percent sodium carbonate as the active ingredient and the rest as other ingredients. The label describes the product as a fungistat and mildewstat, meaning it is aimed at inhibiting growth, and says it can be used on hard and fabric surfaces.

Independent testing shows that surface type matters more than brand. A 2007 study by Menetrez and colleagues, published in Environmental Science and Pollution Research, tested 13 cleaners on gypsum wallboard contaminated with Stachybotrys chartarum over six months. The authors found “the best antimicrobial cleaner to choose is often dependent on the type of surface.” They also stated that the results “are not meant to endorse the incomplete removal of mold contaminated building materials.” In other words, even the best performers did not make moldy drywall worth keeping.

EPA adds one firm warning for all products: do not use fungicides made for outdoor use for indoor mold.

Which approach fits which surface?

Match the method to the material. EPA’s tables sort materials by how they respond to cleaning.

For room-specific advice, see mold in the bathroom and mold on drywall.

Does it matter what kind of mold it is?

No. CDC says, “No matter what type of mold is present, you need to remove it.” No product is recommended for one mold color over another. Dark mold, often called “black mold,” gets the same treatment as any other mold of the same size on the same surface.

Be wary of products or services that claim to remove “mold toxins” from your home or your body. Leading medical groups, including the American Academy of Allergy, Asthma and Immunology and the American College of Medical Toxicology, say urine mycotoxin tests and “mold detox” treatments are not validated. Our mycotoxin testing guide explains why.