For more help with this issue, see how wall leaks are found without removing drywall, ceiling leak emergencies, our emergency leak detection overview, and thermal imaging for hidden leaks.
Supply Line Burst Inside The Wall
Copper and PEX supply lines run through wall cavities to feed fixtures, and a split fitting or pinhole sprays pressurized water into the enclosed space. The wall hides the evidence until paint bubbles or water breaks through. Acoustic listening hears the spray through drywall and marks the break precisely.