Does Bleach Kill Mold Spores?

Bleach has the ability to clean difficult household stains and keep white fabrics looking their best, but it also functions as a powerful disinfectant.

Types of Bleach

As a result, some cleaning professionals advise using bleach as a mold killer. If you plan to attempt it, first understand the pros and cons as well as the necessary precautions.

"Bleach" is a general term that can describe any household bleaching agent. Common household bleach refers to chlorine bleach, a corrosive cleaning solution. Chlorine bleach can completely kill and disinfect mold, but it also emits fumes. Another household bleaching agent, known as peroxygen bleach, or simply oxygen bleach, also kills mold. As opposed to chlorine bleach, oxygen bleach is natural and emits no fumes. It comes from naturally derived, non-corrosive chemicals.

Why it Works

Chlorine bleach contains sodium hypochlorite, a mold-killing chemical compound. Mold removal services use sodium hypochlorite to destroy large colonies. Oxygen bleach kills mold by slowly releasing oxygen ions. Hydrogen peroxide, another natural household bleaching agent, also releases oxygen ions to kill mold. Even after killing mold spores, it's still necessary to remove them from your home. "Killing" simply refers to the process of neutralizing or disinfecting, but even dead mold spores can regenerate if moisture is available.


If you decide to use chlorine bleach, wear rubber gloves, and do not ever attempt to spray or scrub a surface with full-strength bleach. Always start by diluting with water. Depending on the type of surface and the amount of mold, you should use at least three parts water per one part bleach. For really sensitive materials like fabrics and upholstery, you may need only 2 tbsp. of chlorine bleach per 1 qt. of water. When using oxygen bleach, follow the manufacturer's instructions for adding water.

Proper Uses

To get the greatest effectiveness from your bleach solution, pour the liquid into a spray bottle. Spray your bleach gently over the mold, to penetrate the active spores without soaking your household surface. Always let the bleach soak for at least 15 minutes and then rinse the area completely, removing all traces of bleach. Dry the affected surface to prevent new mold spores from germinating.