You may wonder if I have seen this enough for it to be an eco peeve, and the sad fact is I have. People dump crazy amounts of toxic substances down drains, rather then take the time to dispose of them properly according to the law. Last winter there were some renovations going on across the street and I saw the man who'd bought the house dumping paint down the city sewer five times in one week! Sick Mister! It turned my stomach, and my one regret now is that I hadn't gotten a picture of it and called the police. (I know I know, what was I thinking?)
The best solution is to stop this madness of using stuff soooo freaken toxic in our homes, cause who the hell really wants bio hazardous waste on their walls?!? Think about it. If it pollutes the water, the soil and everything else- it's polluting your house too.
So in the meantime what can we do with toxic substances we either no longer want, or have finished using? Call your local garbage pick up or dump to ask where the nearest location is that handles toxic materials. There are special landfills designated for these types of toxic materials, that have "liners" in a massive hole to keep it from seeping into ground water & soil. Also check with Earth 911, that has guides to many city's recycling programs and places to dispose of paint. In the future just stop buying this sh*t, there's an alternative out there - non toxic paint is now available at tons of eco stores on the web, and many local big chains carry no VOC too.