Quick answer
Yes, on hard surfaces. Household 3% hydrogen peroxide is an oxidiser that kills common molds and bacteria on tile, grout, glass, sealed countertops, appliances and painted walls: spray it on, leave it about ten minutes, scrub, wipe and dry. It has a mild bleaching effect that lifts some mold staining, no toxic fumes, and it breaks down into water and oxygen. Like vinegar and bleach, it cannot reach mold that has grown into drywall, bare wood, carpet or ceiling tile — EPA's guidance for those materials is removal — and it must never be combined with vinegar, which forms corrosive peracetic acid. Test fabrics and colored surfaces first; it can lighten them. Call (888) 840-6512 to reach a certified water damage restoration company in your area; the line is answered 24/7.
Press 1 for water damage or 2 for mold, then your 5-digit ZIP. The line goes quiet for about half a minute while it connects — that is normal, stay on.
Written & reviewed by Marcus ReedIICRC WRT
Reviewed August 30, 2026· Next review Feb 2027
The Third Bottle Under the Sink
After vinegar and bleach, hydrogen peroxide is the mold cleaner people ask about most, and it deserves a straighter answer than either. The 3% solution sold in every pharmacy is an oxidiser: it kills common household molds and bacteria on contact, it lightens some of the staining they leave, it has no fumes, and it breaks down into water and oxygen. On hard, non-porous surfaces it is a fair choice. On anything porous it has the same limit every spray has.
Where It Works
| Surface | Peroxide? | Notes |
|---|---|---|
| Tile, grout, glass, porcelain | yes | the shower standard; lifts grout staining better than vinegar |
| Sealed countertops, laminate | yes | test stone — oxidisers can dull some sealers |
| Painted walls and ceilings (surface mildew) | yes | as a cleaner; wall mold removal has the method |
| Appliance interiors, gaskets, plastic | yes | safe on stainless, unlike bleach |
| Fabric, shower curtains | test first | lightens colors |
| Bare wood | limited | surface only; mold in wood grain is sanded or borate-treated |
| Drywall the mold has penetrated | no | replaced, not treated |
| Carpet, padding, insulation, ceiling tile | no | EPA: porous materials may need to be discarded |
How to Use It
- 1Ventilate and protect. Gloves and eye protection; it stings cuts and eyes. An N95 if you are disturbing dry growth.
- 2Spray 3% peroxide undiluted on the surface until wet.
- 3Leave it about ten minutes. The fizzing is oxygen being released as it reacts; contact time is the treatment.
- 4Scrub with a brush or sponge, wipe, rinse and dry the surface completely.
- 5Repeat for stains that lighten but remain; a stain that survives two rounds is in the material.
Store it in its dark bottle — light breaks it down — and expect it to lose strength over a year once opened.
What It Doesn't Do
It doesn't reach porous material. Drywall, bare wood, carpet and ceiling tile hold mold below the surface, and peroxide's water soaks in while its oxidising effect is spent on top. The result looks clean for a few weeks. EPA's guidance for moldy porous materials is removal, and the drywall decision lays out when a wall is cleaned and when it comes out.
It doesn't fix moisture. Every colony is being fed by water — a bathroom ceiling that condenses, a leak, humidity over 60%. Peroxide on the mold and nothing on the water is a monthly appointment.
It doesn't scale. EPA's threshold for professional remediation is about 10 square feet of growth, and anything in HVAC or from a hidden source is a job with containment and HEPA, not a spray bottle.
It doesn't mix. Peroxide with vinegar makes peracetic acid, corrosive to skin, eyes and lungs. Peroxide with bleach releases oxygen violently and wastes both. One product at a time, rinsed between.
Talk to a water damage pro now
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(888) 840-6512- Describe the damage & give your ZIP
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- They quote — you decide, no obligation
Peroxide vs. Vinegar vs. Bleach
For hard surfaces, all three work with scrubbing and drying, and EPA's own recommendation is the plainest of all: detergent and water. Peroxide — no fumes, mild stain lifting, safe on stainless, can lighten colors. Vinegar — gentle, cheap, kills some species and not others, hard on grout and metal over time. Bleach — whitens best, corrodes stainless, fumes, and fails on porous materials in a way that looks like success. Pick by surface. In a shower, peroxide on the grout and a squeegee on the walls beats all three.
Bottom Line
3% hydrogen peroxide kills mold on tile, grout, glass and sealed surfaces with ten minutes of contact and a scrub, lifts some staining, and leaves no fumes. It does not reach mold in drywall or wood, it never meets vinegar in the same bottle or the same hour, and it does nothing about the water that grew the colony — which is the only thing that keeps mold from coming back.
Which Strength
| Product | Concentration | Use on mold |
|---|---|---|
| Drugstore brown bottle | 3% | The right one — enough oxidising power for surface mold, gentle on most finishes |
| "Hair developer" / salon peroxide | 6–12% | Stronger, bleaches fabric and some paint; gloves and eye protection mandatory; no real advantage on hard surfaces |
| Food-grade | 35% | A chemical burn hazard; never for cleaning undiluted, and diluting it to 3% only recreates the drugstore bottle |
| Peroxide-based commercial mold cleaners | 3–8% with surfactants | Work the same way with better wetting; the surfactant is what you pay for |
Higher concentration does not reach deeper into a porous material — it only bleaches the surface harder. On tile and grout, 3% with ten minutes of contact and a brush is the whole method.
Problem Spots
- Silicone caulk with black growth. Peroxide lightens it; the growth is usually behind the bead, not in it. Cut the caulk out, treat the joint, dry it, re-caulk with a mildew-resistant silicone.
- Grout that stays grey. Two rounds of peroxide, then a grout brush; grey that survives is stain in unsealed grout — seal it once it is clean and dry, or regrout.
- Wood furniture with surface mildew. Wipe with peroxide on a cloth (not sprayed — it raises the grain), dry immediately, and move the piece away from the cold wall that grew it.
- Leather, books, papers. Peroxide stains and weakens them; use the leather method and, for paper, dry brushing outdoors.
- Humidifier and dehumidifier tanks. Peroxide is the safe choice where bleach fumes and residue are not; half a cup in the tank, swirl, rinse.
- Washing machine gasket and drum. Peroxide on the folds of the gasket, then a hot empty cycle — the washer version.
Safety and Storage
Peroxide is an irritant to eyes and broken skin and lightens hair, fabric and some paints on contact — test an inconspicuous spot on anything colored. It degrades into water and oxygen in light and heat, so the bottle is brown and belongs in a cupboard; a bottle that no longer fizzes on a cut has lost its strength and will not clean mold either. Never mix it with vinegar in one container (peracetic acid) or with bleach (rapid oxygen release). One bottle, then rinse, then the other if you want both — and for anything beyond about 10 square feet, or anything inside a wall, the cleaner is not the tool.
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Frequently Asked Questions
Is hydrogen peroxide better than vinegar or bleach for mold?
On hard surfaces all three remove surface mold when combined with scrubbing and drying. Peroxide's advantages: no fumes, a mild stain-lifting effect, and it decomposes into water and oxygen.
Vinegar is gentler on grout and metal; bleach whitens stains most but corrodes and does not work on porous materials. None of them reaches mold inside drywall or wood, and none is a substitute for fixing the moisture.
What strength of hydrogen peroxide kills mold?
The 3% sold in pharmacies is the right one for household use — it is effective on hard surfaces with about ten minutes of contact time and is safe to handle with gloves. Higher concentrations are corrosive, bleach surfaces aggressively and are not needed. Do not dilute the 3%; contact time matters more than strength.
Can I mix hydrogen peroxide and vinegar to kill mold?
NoCombined, they form peracetic acid, which is corrosive to skin, eyes and lungs and damages surfaces.
Use one, rinse the surface, and use the other on a separate occasion if you want both — but on a hard surface, one of them plus scrubbing is enough.
Does hydrogen peroxide remove mold stains?
PartlyIts oxidising action lightens many mold stains on grout, tile and light fabrics, which is why it is a common choice for shower grout.
Deep staining in porous material — drywall, unfinished wood — is growth below the surface, and no surface treatment removes it; that material is sanded, sealed or replaced.
Who do I call right now for water damage?
Call (888) 840-6512. The line is answered 24 hours a day, seven days a week, and connects you with an IICRC-certified water damage restoration company that serves your area. A recorded menu picks up first: choose water damage or mold, key in your 5-digit ZIP code, and hold through the short silence while the call is passed to the company.
Describe what you can see — where the water is coming from, how long it has been there, and whether it smells — the more specific you are, the faster the right company is on the line. If the source is a pipe or an appliance, shut the main water valve first. Have four things ready and the call goes quickly: the address, when the water started, what is wet now, and whether you have filed an insurance claim.
Still not sure which of these is your situation? (888) 840-6512 · toll-free · answered 24/7
Sources
- EPA — Mold Cleanup in Your Home
- EPA — Should I use bleach to clean up mold?
- CDC — Mold: Cleanup and Remediation
Methodology: How we source and verify data · Report an error
Disclaimer: HearthDry is an independent educational resource. This article is for informational purposes only and does not constitute professional, legal, or insurance advice. Consult licensed professionals before making decisions about your property or insurance claims.
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