Bleach May Actually Make The Mold Worse

The use of Chlorine Bleach has been a common recommendation for cleaning and killing mold. However, the fact is that bleach is not an effective chemical for killing colonized mold. It may be effective on hard, non-porous surfaces such as shower walls or countertops, but so are other milder, less noxious, solutions using other detergents. Because non-porous surfaces do not allow the mold to take root into the material itself, the mold is actually growing on dust and other debris that may be on the surface and will typically wipe off with ease.

On porous surfaces such as wood and drywall mold takes root (hyphae) in the material and colonizes. Cleaning the mold off the surface with bleach does nothing to kill the roots. In fact, because bleach is 98% water it can actually make the problem worse because the chlorine in the bleach does not soak into the porous materials, but the water in the bleach does. Since mold requires water to colonize and grow it will likely grow back in a few days - worse than it was before the bleach was introduced.

Both OSHA and the EPA have determined that bleach should not be used in mold remediation. True, the EPA used to recommend the use of a bleach solution to clean mold, but has since removed that recommendation.

The goal of mold remediation is to get rid of the mold; not kill it! Dead mold can still release spores into the air and the concentration of mold spores in the air is the main potential for health problems. If you see visible mold growth on building materials, the chances are that there is more that you cannot see (see the post title “I Don’t See Any Mold”). It is best to hire a certified mold inspector to assess the situation and help you decide the proper plan for remediation.