I fly for JetBlue Airways, I fly the A320. I'm based in JFK, live in Michigan, about an hour drive from DTW. I commute ~500 miles to work on other airlines. !!
Been flying for about 30 years now. Can't wait to retire. If I can afford to ....
With your stand alone metal chimney, There definitely is a problem, I'm thinking that the flashing on the roof where the chimney goes through the roofing and shingles. Or maybe the sealing ring around the outside of the chimney where it goes through the flashing ring [ that attaches to the roofing].
The water that is on the outside of of the chimney was clean, right? No soot stains from inside the chimney right??
It is something simple, just have to find it.