Dumping household chemicals down the drain can introduce harmful substances into the water supply and environment. Many household cleaners, pesticides, and other chemicals contain substances that can't be effectively treated by wastewater facilities, leading to potential pollution of rivers, lakes, and groundwater.

In addition to environmental concerns, some chemicals can react with other substances present in the plumbing or wastewater system, leading to dangerous fumes or blockages. Instead of disposing of household chemicals down the drain, it is recommended to take them to a local hazardous waste facility or participate in community disposal events designed for chemicals and other hazardous materials.