Faculty and Staff

Wash and Rinse Water Disposal

Last updated September 8, 2009 2:16:29 PM PDT
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Learn how to dispose of wash and rinse water contaminated with hazardous materials or highly toxic, acidic, or caustic cleaning solutions. Follow these instructions when washing glassware, containers, and equipment.

For other drain disposal questions, see Sewer Disposal: What Can Go Down the Drain?

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1. Determine if wash and rinse water must be collected as hazardous waste or can go down the drain.

  • Wash and rinse water can go down drains if it is:
    1. Nonhazardous
    2. Liquid
      • No solids, sludges, or viscous substances
    3. Nondisruptive to sewage treatment operations
      • No corrosive pH levels
      • No grease or oil
      • No hot (150° or higher) temperatures in volumes of more than 10 gallons
  • If wash and rinse water is contaminated with hazardous material or toxic, acidic, or caustic cleaning solutions, or otherwise do not meet the drain disposal criteria above, do not pour it down the drain. Go to Step 2.

2. Empty, wash, and rinse equipment and glassware.

  • Empty the contents of equipment and glassware that held hazardous materials into an appropriate hazardous waste storage container.
  • Wash with a small amount of water or appropriate solvent and empty the rinse water into the hazardous waste storage container.
  • Rinse and empty once more.
  • Wash the equipment. Detergents, wash water, and rinse water can go down the drain unless highly caustic, acidic, or toxic cleaning solutions are used. These include:
    • Chromerge
    • Sodium hydroxide
    • Sulfuric acid
    • Hydrochloric acid
    • Phosphoric acid wash solutions
    Avoid using these solutions if possible.
  • Collect highly caustic, acidic, or toxic wash water by emptying it into the hazardous waste storage container.
    • Capture the first rinse and do either of the following:
      • Direct rinse water back into the wash solution, using it for the next wash
      • OR
      • Empty rinse water into the hazardous waste container
    • Additional rinses can go down the drain.

3. Dispose of the hazardous waste storage containers.

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If you have questions, contact EH&S Environmental Issues Program, (858) 534-3660.

Notice: Disposal of hazardous waste using sinks, intentional evaporation, or as regular trash is against the law. Campus laboratories must abide by strict state and federal waste disposal requirements. You may be held liable for violations of applicable laws.