It isn't exactly advertised, but the city water around the cmu-google-downtown region has failed tests many times, and at least on two occasions the city provided water filters due to contaminants. This is mostly due to how old the city is, rusty and lead pipes in old homes are impossible for the city to track and fix. This is true everywhere in the rust belt.
Air quality in Pittsburgh gets really bad once you go out past googles neck of the woods, that used to be covered in steel mills, plastics manufacturing, coal and trash burning plants. I understand the desire to live near work, but please don't move near bakery square. They can try to cover it up, but I'm sure the ground is contaminated as well. The entire thing used to be a factory before they bulldozed it in the early 2000s. And nearly all the land near a river will have been used by industry at some point. There's a reason why you can pick 4 locals and at least one has asthma.
Edit: for fun, here's a reminder of what the city looked like during the steel days. You couldn't wear white clothing because of the soot in the air. http://cdn.citylab.com/media/img/citylab/legacy/2012/06/05/p...