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Why Bleach is NOT the Best Way to Kill Mold

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Home Inspector with All American Inspections & Testing LHI#10501

Why Bleach is NOT the Best Way to Kill Mold

Many people believe bleach is the best solution for mold removal, but that’s a myth. While bleach may whiten mold stains, it does not kill mold at its roots, and in many cases, it can make the problem worse.

Why Bleach is Ineffective Against Mold

  • Bleach Only Works on Non-Porous Surfaces

    • It can disinfect tile, glass, and countertops, but it does not penetrate porous materials like drywall, wood, or concrete. Mold grows deep into these surfaces, and bleach only affects the surface layer.
  • Bleach Can Make Mold Worse

    • Bleach contains a high percentage of water. When applied to porous surfaces, it feeds the mold underneath while only killing surface-level spores. This allows the mold to return even stronger.
  • Bleach Does Not Remove Mycotoxins

    • Some molds, such as Stachybotrys (black mold) and Chaetomium, produce mycotoxins that linger even after the mold is gone. Bleach does not neutralize these harmful toxins.
  • Bleach Evaporates Quickly

    • While bleach can kill some mold spores on hard surfaces, its effects are temporary because it evaporates quickly, allowing mold to regrow if moisture is still present.

What to Use Instead of Bleach

  • Botanical Mold Cleaners – Products containing thymol (thyme oil) are EPA-approved for mold remediation and safer for indoor use.
  • Hydrogen Peroxide (3% - 10%) – Breaks down mold at the root and does not leave toxic residue.
  • White Vinegar – Kills many mold species and helps prevent regrowth.
  • Professional Mold Remediation – If mold is spreading or inside walls, professional testing and treatment may be needed.

Bleach is NOT the solution for mold problems. Proper removal and moisture control are the only ways to effectively eliminate mold and keep it from coming back.

 

https://www.epa.gov/mold/should-i-use-bleach-clean-mold

Comments(6)

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Dorie Dillard Austin TX
Coldwell Banker Realty ~ 512.750.6899 - Austin, TX
NW Austin ~ Canyon Creek and Spicewood/Balcones

Good evening Dan,

I can see why Bleach is NOT the solution for mold problems and the only real solution is proper removal and moisture control.

Mar 06, 2025 06:44 PM
Kathy Streib
Cypress, TX
Retired Home Stager/Redesign

Hi Dan- I learned quite a bit in your post and I'm glad I have peroxide as well as clorox. During Covid, I remember everyone was searching for something that would kill germs, etc when supplies were running short. 

Mar 06, 2025 07:07 PM
Sham Reddy CRS
Howard Hanna RE Services, Dayton, OH - Dayton, OH
CRS

Thanks Dan for sharing great information on mold remedies!!!

Many people believe bleach is the best solution for mold removal, but that’s a myth. While bleach may whiten mold stains, it does not kill mold at its roots, and in many cases, it can make the problem worse.

Mar 07, 2025 03:47 AM
Michael Jacobs
Pasadena, CA
Pasadena And Southern California 818.516.4393

Hello Dan - sometimes while we may think we are helping a situation, we are making it worse.  Oh, those unintended consequences.  Thank you for the post.  

Mar 07, 2025 04:14 AM
Kat Palmiotti
eXp Commercial, Referral Divison - Kalispell, MT
Helping your Montana dreams take root

Interesting reasons why bleach is not the best way to kill mold. I haven't had to get rid of mold, but would have thought of bleach as a solution. Glad to have this information.

Mar 07, 2025 05:14 AM
Dan Paradela

Of course! Its something we come across a lot when our clients tell us that they tried fix their problem with bleach and wonder why it came back worse! 

Mar 07, 2025 09:14 AM
Brian England
Ambrose Realty Management LLC - Gilbert, AZ
MBA, GRI, REALTOR® Real Estate in East Valley AZ

I have never had to remediate mold myself, but I am definitely going to keep this in mind in case I ever have to, haha.

Mar 07, 2025 06:25 AM