You can't report what you can't see.

Infrared Imaging 

Infrared imaging is taking pictures of temperatures. A cold spot can indication mold, excessive moisture or missing insulation behind walls. A hot spot can identify overheated wiring or leaking exhaust. 

Water Leak and Potential Mold Behind Wall.

Toilet Leak Under Flooring.

Roof Leak

100°F Circuit Breaker is Safe, but you get the Point. 

---

Borescope Imaging

Well, you can see just about anywhere with a borescope. And they're waterproof.