Sent by NatalieEditor: Natalie, this is a great question, and as it happens, one of our readers, Nina, sent us an article she had written for Slate magazine on this very topic! Here's an excerpt:
It's true that cleaning your painting tools can be a water-intensive process. As with cars and dishes, though, there's a big difference between an efficient washing regime and a wasteful one. Choose the former, and there's no reason to violate one of the most basic tenets of green living: thou shalt choose durable over disposable.
First off, make sure you're using a water-based paint as opposed to a solvent-based one. Water-based paints—which account for the vast majority of the American market—have much lower levels of air-polluting volatile organic compounds; plus, they don't require strong chemicals for cleanup. To find certified low-VOC paints, look to the third-party organizations Green Seal, EcoLogo, or Green Guard.
To clean water-based paint off a dirty brush, all you'll need is soap and some running water. A lot of running water: Most people wash their brushes with something like a five-minute rinse under the faucet—or about 11 gallons from the local reservoir. That's enough water per brush to do three loads of dishes in an ultra-efficient machine.
Read the rest of her answer here.
Other thoughts for Natalie?