What Is Household Hazardous Waste

Household hazardous waste (HHW) refers to chemical wastes and materials typically used within a household such as paints, cleaning solutions, oil, batteries, and pesticides. Since these wastes and materials may be corrosive, toxic, or flammable, they should ALWAYS be disposed of at a HHW facility—NOT with household garbage. For safety and environmental reasons, it is illegal to dispose of HHW in the garbage, sewers, or storm drains. Please report any illegal dumping you may see.

Problems with Improper Disposal of Household Hazardous Waste

  • Contaminates our waterways and drinking water
  • Physical injury to sanitation workers
  • Contaminates septic tanks or wastewater treatment systems if poured down drains or toilets
  • Presents hazards to children and pets if left around the house
  • Harms wildlife and the environment

Proper Disposal of Hazardous Wastes

The HHW Program is a free recycling and disposal service for San Mateo County residents only. Residents must make an appointment and limit waste to 10 gallons or 50 pounds per appointment. Please note that empty containers are not hazardous waste and can be recycled. Leave the lids off so waste haulers can see that the container is empty and non-hazardous.

Examples of accepted wastes include:

  • Aerosol spray cans (except food grade products like cooking oil sprays)
  • Art and hobby supplies (photo chemicals, glues)
  • Automotive supplies (car batteries, motor oil, antifreeze, brake fluid, gasoline, fuel additives, chrome polish, many waxes)
  • Fluorescent lights
  • Garden fertilizers, herbicides, and pesticides
  • Household cleaning chemicals 
  • Paint thinner
  • Poisons
  • Pool and spa chemicals
  • Propane tanks from barbecues
  • Thermometers that contain mercury

For a full list of accepted and unacceptable waste and alternative disposal options, click here.

Other Common Household Items