What kills mold?
- Mold
Bleach, vinegar, hydrogen peroxide and alcohol all kill mold on a hard surface. EPA still does not recommend routine biocide use during cleanup, because killing mold is not removing it — dead mold continues to cause allergic reactions. Detergent and water, followed by drying, is what EPA actually publishes.
The short version
- EPA — "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."
- Biocides are "not recommended as a routine practice during mold cleanup", with an exception EPA notes for immunocompromised occupants.
- Nothing kills mold permanently. A background level of spores always remains, and stays harmless as long as the moisture is gone.
- Never mix chlorine bleach with ammonia or any other cleaner — it produces toxic gas.
- If you do use a disinfectant, EPA says ventilate the area and exhaust the air outdoors.
What actually kills it, and why that is the wrong question Link to this section
Chlorine bleach kills mold on a hard, non-porous surface. So do hydrogen peroxide, undiluted white vinegar, and 70% isopropyl alcohol. None of that is in dispute, and none of it is the point.
EPA’s answer to “should I use bleach to clean mold” contains the sentence that reframes the entire subject:
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.
The allergen is a protein in the mold structure. It does not stop being an allergen when the organism dies. A wall that has been sterilized and left in place is a wall that still has mold on it — now dead, still there, still capable of triggering the stuffy nose, cough, wheeze, burning eyes or skin rash that CDC lists.
This is why EPA’s published method is not a biocide at all. It is detergent, water, and drying: a mechanical removal, followed by taking away the condition that let it grow.
EPA’s actual position on biocides Link to this section
The use of a chemical or biocide that kills organisms such as mold (chlorine bleach, for example) is not recommended as a routine practice during mold cleanup.
EPA does note a circumstance where it may be appropriate — situations involving immunocompromised occupants — and gives conditions for using one at all:
- Never mix chlorine bleach solution with other cleaning solutions or detergents that contain ammonia, because toxic fumes could be produced.
- Always ventilate the area and exhaust the air to the outdoors if disinfectants are used.
CDC, which is more permissive about bleach for household cleanup, adds a dilution and a set of protection: no more than one cup of bleach in one gallon of water; open windows or doors for fresh air; at least a NIOSH-approved N95 respirator, non-latex gloves, and goggles that give complete eye protection.
“Permanently” is not available Link to this section
Searches for what kills mold permanently are asking for something that does not exist, and the reason is not a product failure.
There is no practical way to eliminate all mold and mold spores in the indoor environment.
Spores are in the outdoor air and come in through every door and window. A background level will always be present. EPA’s own framing of the outcome is the useful one: these spores will not grow if the moisture problem has been resolved.
Permanence, in other words, is a property of the building, not of the bottle. The house that never grows mold again is the one that stays between 30 and 60 percent relative humidity with no leak running, whatever was used on the wall last year.
Where products stop mattering entirely Link to this section
On porous material — carpet, padding, ceiling tile, insulation, the paper facing on drywall, upholstery, untreated wood — growth is inside the material rather than on it. Nothing sprayed on the surface reaches it. EPA’s guidance for those materials is replacement, and no product changes that arithmetic.
What this means for your claim
Product choice has no bearing on coverage, and it is worth knowing what does. Adjusters and their consultants look at the cause and duration of the water, not at what was used to clean up afterwards.
One product decision can cost you, though. If you clean, repaint and dispose of the material before anyone documents it, you have removed the evidence that the mold followed a sudden covered event rather than a long-running one. That is the distinction between a claim within the mold sublimit and no claim at all, and it is decided on photographs.
What comes next
Whatever you use, the growth returns unless the water stops. See mold and the drying window, and water categories if the source was a leak or a flood rather than humidity.
Common mistakes
- Treating "kill" and "remove" as the same job. EPA's position is that they are not, and that removal is the one that matters.
- Mixing bleach with ammonia, or with a detergent that contains it. The result is a poisonous gas.
- Spraying a biocide on porous material and calling it done. It does not reach growth inside the material.
- Believing any product prevents recurrence. Nothing does, except removing the moisture.
- Using a disinfectant in a closed room. EPA says to ventilate and exhaust the air outdoors.
Common follow-up questions
Is vinegar better than bleach?
On a hard surface both kill many molds, and neither removes the residue on its own. EPA recommends neither as routine practice — its published method is detergent and water followed by complete drying. Vinegar has one practical advantage worth naming, which is that it cannot produce a poisonous gas if it meets an ammonia-based cleaner.
Does bleach work on drywall?
Not on the growth inside it. Bleach is mostly water, and on a porous surface the water soaks in while the chlorine stays near the top. Mold growing in the paper facing survives, and the added moisture is exactly what it wanted.
What about mold bombs, foggers and UV lights?
EPA does not recommend routine biocide use in any delivery form, and fogging a room does not remove anything. The same objection applies to every sterilization-only approach — dead mold left in place is still an allergen, and the moisture that grew it is still there.
Sources
Every source cited on this page
- T1Should I Use Bleach to Clean Up Mold? — US EPA (accessed 2026-08-25)
- T1A Brief Guide to Mold, Moisture and Your Home — US EPA (accessed 2026-08-25)
- T1Mold Clean Up Guidelines and Recommendations — CDC (accessed 2026-08-25)
- T1About Mold and Health — CDC (accessed 2026-08-25)
Also asked as
What kills mold mildew? · What kills.mold? · What kills mould? · What kills mold permanently? · Does alcohol kill mold? · Does ammonia kill mold? · Does amonia kill mold?