I think a few people have made homebrew versions too, like this one mentioned on HN: https://news.ycombinator.com/item?id=45137584
fluke $25k
flir $10k
td2 $1k
These are the kinds of things you look at and think - maybe I DO need night-vision, or a soldering iron with a cpu, or a thermal imager, or a steerable endoscope or now an acoustic imager....
Could one of these tools help map water pipe routes and trace a leak, or are they only going to be useful for air and gas leaks?
You should definitely try a thermal camera. Any moisture will create small temperature differences which are easily picked up by a thermal camera.