Bleach kills bacteria and viruses and sanitizes the surfaces it's used on. Bleach also kills mold if it comes into contact with it. The spores and allergens from mold are neutralized as well.
Bleach will kill mold growing on non-porous surfaces
like fibreglass, glass, tiles, bathtubs and counter tops.
However bleach cannot completely kill mold growing in non-porous materials
, carpet, drywall, and wood. Bleach does not penetrate into these non-porous substances and so only the mold growing above the surface is killed. Molds have roots (hyphae) and bleach’s ion structure stops chlorine from penetrating porous materials, therefore when you spray all the chemicals are going to stay on top of your surface while the water part of the solution just soaks through. Bleach won't kill mold on dirty, metallic or porous substances either.
OSHA was the first federal agency to announce a departure from the use of chlorine bleach in mold remediation