General rules:
(1) Check with your local government about what chemicals can and cannot be poured into the waste water system.
(2) Identify those chemicals that are not compatible with your building's plumping system.
(3) Concentrated acid and bases must be neutralized before disposal.
(4) Flammable solvents should either not be poured down a sink or else made sufficiently dilute as to be nonflammable.
(5) Solutions should be dilute before disposal. This can usually be achieved by having water running when pouring the solution down the drain.
(6) Care should be taken to prevent splashing of the solutions onto people and non-sink surfaces.
(7) Do not dispose of a chemical that may be reactive with another chemical disposed of earlier or in a different part of the building.
(8) Do not pour heavy metals, carcinogens, potent toxins, or chemotherapeutic agents (hazardous chemicals) down a sink.
