If it is not biodegradable it shouldn’t go down the drain.
Wastes like acetone, which are highly flammable, are dangerous to pour down the drain. Less obvious are wastes like paints that may contain solvents or metals like mercury, chromium, and lead.
Organic solvents are found in enamel and primer paints, stains, and varnishes. When painting try to use latex or water based paints. Pesticides are a household waste that is highly toxic. Used motor oil and antifreeze contain heavy metals such as lead. Hobbyists use a variety of chemicals that can cause problems for the treatment plant.
Amateur photographers should be aware that photographic fixer usually contains high amounts of silver. They should contain their fixer and dispose of it at the City's Household Hazardous Waste Collection Center instead of pouring it down the drain.
Items That Cannot Go Down the Drain Never put the following items down the drain:
Cleaning products (such as products with words like toxic, corrosive, flammable, or ignitable mentioned on the label)
Automotive products (such as motor oil, antifreeze, brake fluids)
Garden supplies (such as pesticides, herbicides, fungicides)
Paints and solvents (such as latex and oil-based paints, thinners, strippers) Do not clean oil-based paintbrushes in the sink
Art and hobby supplies – (such as paints, photographic chemicals, glues)