Household bleach is a versatile tool. You can use it to clean, disinfect and to kill mold and mildew inside your home. Household bleach can kill also kill plants, including grass.
Bleach and Grass
Household bleach will kill grass if enough is poured onto the grass. In small exposures, bleach will cause grass to yellow and the blades to curl. In greater quantities, bleach penetrates grass, destroying its tissue inside and out, killing it.
Using household bleach to kill grass can also kill other nearby plants. If the bleach penetrates the soil, you will not grow anything else in that area until the bleach is washed away. Bleach in the soil and on grass can be a hazard for children and pets that play in the yard.
Instead of using bleach on lawn pests like algae or mold like powdery mildew, use algaecides and fungicides. These products are designed to target the problematic organisms, rather than damaging everything with which they come in contact.