What Is Paint Rinse Water — and Why Can't You Pour It Down the Drain?
When you're painting, you're usually focused on colors, finish, and working neatly. But what do you do with the water you use to clean your brushes or painting tools? This so-called paint rinse water might seem harmless, but it’s anything but. Pouring it down the sink or toilet can have serious consequences for the environment and water treatment systems.
What is paint rinse water?
Paint rinse water is the water used to clean paintbrushes, rollers, or spray equipment. It often contains leftover paint, solvents, pigments, heavy metals, and other chemical substances. Whether you're using water-based (acrylic) paint or solvent-based paint, the rinse water left behind is essentially contaminated wastewater.
Why can’t you just pour this water down the drain?
- Harmful to the environment
The chemicals in rinse water can pollute rivers, streams, and groundwater. Even water-based paints often contain microplastics, pigments, and preservatives that are harmful to aquatic life. These substances are difficult or impossible to break down in nature. - Overloading water treatment facilities
Wastewater treatment plants are not equipped to fully filter out paint chemicals and solvents. As a result, these harmful substances can end up in surface water or disrupt the treatment process.