Waste is considered hazardous when it has properties that make it dangerous or potentially harmful to human health or the environment. Hazardous waste can be liquids, solids, contained gases, or sludges. Household hazardous waste is generated in a home rather than a business or organization. Examples include paints and stains, cleaners, aerosols, laundry products, batteries, yard and garden products, thermostats, compact fluorescent light bulbs, electronics, and pharmaceuticals. Federal requirements regulate management of hazardous waste generated by industries, but household hazardous waste is not regulated and therefore may be disposed of in a municipal solid waste landfill. Furthermore, in Idaho, waste from conditionally exempt small quantity generators (businesses generating less than 220 pounds of hazardous waste each month) can be disposed of in a municipal or nonmunicipal landfill through a conditional exemption in the hazardous waste regulations. Leachate from household hazardous waste can leak from landfills and contaminate ground water sources. Additionally, if waste is improperly disposed of down the drain or gutter, public drinking water supplies can be contaminated.

Household hazardous waste diversion programs or events—such as reuse programs, collection events, permanent drop-off sites, business partnerships, or exchange programs—can help to protect ground water. Cities and counties are typically the most appropriate entities to coordinate a program or event as they already have an established infrastructure and system for garbage collection, management, and fees. However, numerous opportunities exist for partnerships including with nearby cities or counties, fire departments, health districts, and state or federal agencies.