Mold removal: Will bleach remove my mold?

Molds are nature’s decomposers, and are responsible for breaking down and getting rid of dead organic material. They definitely have their place in nature, but not in our homes or businesses which is why it’s important to dry out a home quickly when you’ve suffered water damage.

Mold trapped in homes is extremely dangerous, and toxic varieties can cause many problems, including severe illness and the complete destruction of property. Once mold is discovered action should be taken immediately to prevent further issues. Unfortunately when it comes to getting rid of mold the first thing people reach for is the bottle of bleach under the kitchen sink, but it can and does make the problem worse. Bleach can actually feed the very thing you are trying to get rid of. There are various reasons why chlorine bleach should not be used for the clean up of mold. It’s for these reasons that chlorine bleach is not registered as a disinfectant to kill mold with the Environmental Protection Agency (EPA).

Taken from the EPA website:
"It is necessary to clean up mold contamination, not just to kill the mold. Dead mold is still allergenic, and some dead molds are potentially toxic. The use of a biocide, such as chlorine bleach, is not recommended as a routine practice during mold remediation"

Taken from the Centers for Disease Control and Prevention (CDC) website:
"Mold growth can be removed from hard surfaces with commercial products, soap and water, or a bleach solution of no more than 1 cup of bleach in 1 gallon of water."
Note they specify "hard surfaces"


There are quite a few reasons why chlorine bleach is ineffective at killing mold:

Firstly, chlorine bleach does not have the ability to cut through a dirty surface. Bleach cannot clean dirt and only masks it by bleaching it white or transparent. Any soiled surface that requires mold restoration will initially require cleaned before being disinfected with bleach. This is twice the amount of work required to get rid of mold than if the correct product was used in the first place. In addition, the killing power of bleach is quickly deactivated by organic material.

Secondly, even full strength chlorine bleach is too diluted to get rid of mold permanently especially on porous surfaces. The chlorine itself will not soak into porous materials such as drywall and wood, but the water making up 99% of chlorine bleach does, and feeds the mold. Mold grows its roots deep into the surface of drywall and wood and the chlorine can only kill what is on the surface, allowing the roots of the mold to remain very much alive. Mold removal of porous materials is only safe way of getting rid of all the mold.

Lastly, whatever killing power chlorine bleach does posses drops rapidly even over a very short period of time. Apart from the fact that the disinfecting power of bleach is quickly deactivated once it comes into contact with organic material, chlorine bleach also has a very short shelf life. As the bleach sits on the grocery store shelf or in the cupboards in a home, the Chlorine ions continually bleed through the plastic which is why bleach smells like bleach even when the bottle is closed. It is reported that in just the first three months after being bottled there is a 50% loss in killing power in an unopened container of bleach.

The EPA, various Departments of Health, the Wall Street Journal, and even Clorox themselves, have all stated that bleach is ineffective at killing mold on porous surfaces. The Institute of Inspection, Cleaning and Restoration Certification (IICRC), Clorox, the EPA and OSHA, have all stated that bleach should never be used in mold remediation. Bleach appears to kill mold, but just the surface mold is affected – the hidden mold underneath the surface is alive and well – now it’s been fed and doing better than ever.

When the mold eventually grows back, and it will, it will be stronger than before. Bleach seems to help, but it makes the problem worse. There are ways to get rid of your unwanted houseguest, but bleach is not one of them. Call a local professional restoration company like PuroClean Home Rescue (866-722-7876) instead and they will instruct you that killing mold is not good enough; you must get rid of the porous material too.