Solvents Hazardous Waste Illegal in Garbage & Drains Unused or leftover solvents should be disposed of as household hazardous waste. Find out what to do with household hazardous waste Never Dump Down the Drain Keep drinking water supplies clean by not dumping solvents down the drain. Solvents can threaten human health and poison fish species by leaching into lakes and rivers. Ways to Reduce Switch to a Water-Based Solvent Unlike organic food, organic solvents are the less healthy choice since they are known carcinogens. Try switching to water-based solvents that do not contain benzene, carbon tetrachloride, or trichloroethylene.