When people find mold at home, the first move is usually a trip under the sink: bleach, vinegar or hydrogen peroxide. All three can help on the right surface. None of them fixes the reason the mold showed up. Here’s the honest breakdown.
Does Bleach Kill Mold?
On hard, non-porous surfaces like tile, glass and sealed countertops, bleach can kill surface mold and remove the stain. On porous materials like drywall, wood, grout and fabric, it’s a different story. Bleach mostly stays on the surface and whitens the stain, while mold growing inside the material can survive. Bleach is also mostly water, and water is what mold needs.
The EPA’s general guidance is that killing mold with bleach usually isn’t the goal; physically cleaning it off and fixing the moisture is. If you do use bleach, ventilate well, wear gloves, and never mix bleach with ammonia, vinegar or other cleaners. Those combinations can release toxic gases.
Does Vinegar Kill Mold?
Plain white vinegar can work on some common household molds, especially light growth on hard surfaces. Spray it on undiluted, let it sit about an hour, scrub, then wipe and dry. It’s milder than bleach and doesn’t bleach colors, but it’s not strong enough for heavy growth, and it won’t reach mold deep in drywall or wood.
Does Hydrogen Peroxide Kill Mold?
Regular 3% hydrogen peroxide from the pharmacy can kill mold on surfaces and lightens stains. Spray it on, let it bubble for about 10 minutes, scrub and wipe dry. Test it first on fabric, grout or colored surfaces, since it can lighten them.
Quick Comparison
| Bleach | Vinegar | Hydrogen Peroxide (3%) | |
|---|---|---|---|
| Best on | Tile, glass, sealed surfaces | Light growth on hard surfaces | Hard surfaces, some grout |
| Porous materials | Not effective below surface | Not effective below surface | Not effective below surface |
| Watch out for | Fumes; never mix with other cleaners | Smell; weaker on heavy growth | Can lighten colors |
What Matters More Than the Cleaner
- Fix the moisture. A leak, an AC drain line, poor bathroom ventilation or high humidity will bring mold right back.
- Remove what can’t be cleaned. Moldy drywall, carpet pad and insulation usually need to come out.
- Dry everything completely. In South Florida, that often means running the AC and a dehumidifier.
When to Stop Scrubbing and Call a Pro
- The moldy area is larger than about 10 square feet (the EPA’s rough cutoff for DIY)
- The mold comes back after you clean it
- It’s on drywall, ceilings, or anywhere there was a leak or flooding
- Someone in the home has asthma, allergies or a weakened immune system
For specific spots, see removing mold from a bathroom ceiling and how to identify black mold.
Free Visual Mold Inspection in South Florida
If cleaning isn’t solving it, FL Cleanup offers a free visual inspection with moisture readings and an infrared (thermal) camera to find where the water is coming from. When it’s beyond a DIY job, we handle licensed mold remediation across South Florida. We answer 24/7, and hablamos español. Call 877-224-2532 or request a free visual inspection online.
About the author: James Rice-Peña is the owner of FL Cleanup and a Florida-licensed Mold Assessor (MRSA4035) and Mold Remediator (MRSR4158). He has worked in property restoration in South Florida since 2012, and FL Cleanup has earned 200+ five-star Google reviews.
