Does Bleach or Vinegar Kill Mold?

Yes — undiluted white vinegar kills most household mold species, and unlike bleach it penetrates porous surfaces enough to reach some of the root structure. Spray undiluted 5-6% white vinegar on the mold, leave it for at least an hour, scrub, and dry the surface completely.

Vinegar's acidity (around pH 2.5) disrupts mold growth on drywall, wood, and grout better than bleach does, which is why it's the better default for home use. Its limits are real, though: it may not kill every species, it can etch natural stone, and no spray treatment fixes mold that has colonized deep into drywall or insulation.

The unglamorous truth: what you treat matters less than what you fix. Mold killed with vinegar returns within weeks if the moisture that fed it is still there.

Bleach kills surface mold on hard, non-porous materials — tile, glass, tubs, countertops — but it does not work on porous materials like drywall and wood. Bleach's chlorine stays on the surface while its water content soaks in, killing the visible growth and leaving the roots (hyphae) alive and, sometimes, better watered.

This is why bleached mold famously comes back: the surface looks clean for a week or two, then the surviving root structure regrows. The EPA and most remediation standards don't recommend bleach for routine mold cleanup on porous building materials.

If you do use bleach on non-porous surfaces: 1 cup per gallon of water, ventilate well, never mix with ammonia or vinegar (toxic gas), and dry the area thoroughly afterward.

Clorox and similar disinfecting wipes can remove light surface mold from hard, non-porous surfaces, but they don't reliably kill established mold and do nothing against growth inside porous materials. They're fine for wiping mildew film off a bathroom counter; they are not a mold treatment.

Wiping also physically spreads spores if the growth is established — you can smear a small colony across a larger area. For anything beyond light surface film, use a purpose-appropriate treatment and address the moisture source.

For small areas (under about 10 square feet) on cleanable surfaces: undiluted white vinegar or 3% hydrogen peroxide, dwell time of an hour, scrubbing, complete drying, and — the step that actually determines success — fixing the moisture problem. For porous materials with established growth, removal and replacement of the material is the reliable fix, not any liquid.

Humidity control is the second half of every mold fix. Keep indoor humidity below 50%, ventilate bathrooms and kitchens, and dry any water intrusion within 24-48 hours. Mold is biology: remove water and it cannot grow, no matter the species.

Call a professional when mold covers more than about 10 square feet, returns after cleaning, follows water damage, grows inside walls or HVAC, or produces a musty smell you can't locate. These are the signatures of established colonization that surface treatments cannot reach.

Professional remediation isn't a stronger spray — it's containment, HEPA filtration, removal of colonized materials, and moisture correction, performed to IICRC S520 standards. Scrubbing at a symptom of a wall-cavity colony wastes weeks that the mold uses to spread; if the signs point past the surface, get an assessment.