Vinegar or Bleach on Mold: What Each One Does, and the Study Nobody Reads

By John Calhoun, owner of Mold Remediation Gettysburg PA · Updated October 26, 2026

Asking whether vinegar or bleach is better for mold is a little like asking whether a mop or a bucket fixes a roof leak. Neither one fixes the reason the mold is there. That said, people reach for one or the other every day, so here’s an honest side-by-side. The short version: bleach is labeled for hard, nonporous surfaces and whitens growth on porous ones; vinegar has much less evidence behind it than the internet suggests; and the EPA’s own recommendation for hard surfaces is detergent and water. Never, under any circumstances, put the two together.

The study everybody quotes, and what it actually tested

Search for vinegar and mold and you’ll find a 2015 paper cited as proof that vinegar beats bleach. It’s worth reading past the headline. The study, by Rogawansamy and colleagues in the International Journal of Environmental Research and Public Health, tested several household antifungal agents against two common indoor molds, Aspergillus fumigatus and Penicillium chrysogenum.

Here’s what it found and what it didn’t:

• It did not test bleach. There’s no bleach comparison in it.
• It did not test walls, wood or drywall. The tests were on lab plates, not building materials.
• Vinegar worked on one mold and not the other. At 4.0 to 4.2% acetic acid, vinegar inhibited the Penicillium but had no effect on the Aspergillus.
• The authors flagged a weakness. They noted vinegar’s lack of persistence on surfaces may limit its use.
• Tea tree oil came out on top in their tests, and 70% ethanol did nothing against either mold.

A 2019 review by New Zealand’s government science institute called the scientific evidence on mold cleaners very limited, and the only vinegar test it cited was this same lab-plate study. That’s a thin foundation for a cleaning myth this popular.

Side by side

The last row is the honest one. In both cases, what removes mold from a hard surface is the scrubbing that lifts it off and the drying afterward. That’s the method the EPA’s homeowner guidance actually spells out: water and detergent, then dry the surface completely.

Never together, and not one after the other

This is the part worth remembering if you forget everything else. Washington State’s health department explains that when bleach is mixed with an acid, chlorine gas is given off, and it names vinegar as one of those acids. New Jersey’s health department warns against a different DIY combo too: hydrogen peroxide and vinegar mixed together form peracetic acid.

The risk isn’t only pouring two jugs into one bucket. It’s spraying vinegar on the shower tile on Saturday and following up with bleach before rinsing, or using a bleach-based cleaner over a vinegar-soaked rag. Pick one, rinse with plain water before switching, and ventilate. For health questions, start with the CDC’s mold pages.

Watch what you’re spraying it on

Vinegar’s acid is a problem on stone. The U.S. General Services Administration’s historic preservation guidance notes that acids, including vinegar, etch stone by dissolving calcareous stone such as marble and limestone. Older houses can have stone in places you don’t expect, like a threshold, a hearth or a window sill. Test a hidden spot, or skip the vinegar.

In the borough, the Census Bureau estimates nearly half of homes were built before 1940 and about 87% before 1980, so a lot of the surfaces people are spraying are old plaster, old wood and old masonry. Those are porous, which is where neither product shines. The Gettysburg housing data page has the breakdown, and if the white stuff you’re looking at is on a basement wall, check efflorescence vs. mold first. A vinegar fizz there is a clue about salt, not a cleaning method.

Circling back to the roof leak

So which wins? For a small spot on tile, either will lighten it, and detergent and water will remove it. For anything on wood or drywall, neither one is the answer. Fix the water, then clean or remove what’s grown. The details on bleach are in does bleach kill mold, and the case for plain soap is in does dish soap kill mold.

This is John Calhoun at Mold Remediation Gettysburg PA. If you’ve worked through both bottles and the spot keeps coming back, I’ll find the moisture behind it. You can read how I approach a job on the mold remediation in Gettysburg, PA page, and what that includes on the list of mold services.