The District and city service departments do not accept latex paint as household hazardous waste because it is not a hazardous material. Latex paint is 99% water and 1% rubber, and is safe to dispose with your household trash when it is dried out. Here are step-by-step instructions for disposing of latex paint.
To solidify latex paint
* Air dry.
Remove the lid and allow the liquid to evaporate. This works well for small quantities of paint (an inch or two in the bottom of the can), and can take several days.
* Use a drying agent. Mix an equal amount of an absorbent material into the can and allow the paint to dry. Use cat litter, sawdust, plaster of Paris, Oil-dry, or “waste paint hardeners” found at home improvement centers. The paint could dry quickly, depending on how much drying agent you include in the can.
* Pour thin layers (about 1" of paint) into a cardboard box lined with plastic. Allow the paint to dry one layer at a time until all paint has hardened.
* Once the paint is thoroughly dry, place it in a regular trash bag and put it out with your weekly rubbish collection.
* DO NOT dump the paint on the ground or down storm drains where it will travel directly to surface and/or ground water.
* DO NOT pour paint down the drain. While small amounts of latex paint can safely be washed down the drain to a septic system or wastewater treatment plant, this practice should be kept to a minimum. Limit this to brush cleaning and other clean-up.
* DO NOT throw liquid paint in the regular trash. Leaking paint spills out of waste collection vehicles onto city streets making an unsightly mess that is very difficult to clean up.
* Buy the correct amount of paint for your project. Determine how much paint you’ll need via a paint calculator offered by your local home improvement or decorating store website, or use a mobile app.
* Not sure if you’ll like a color? Use paint swatches first or purchase a sample size.
* Be creative and use up any paint that you have left over. Paint a birdhouse, a garage wall, or outdoor furniture.
Donate large quantities of good, usable latex paint to a local theater group, development corporation, or neighborhood improvement project. Make sure the paint is not contaminated with particulates, and it should not have gone through a freeze-thaw cycle. See the list below. Call ahead first to make sure that your donation will be accepted.