Leak at garage ceiling below below master shower. Another plumbing company had already cut access in the ceiling but they were unable to diagnose the issue. We performed a shower pan test by plugging master shower drain and filling the shower pan to a height of two inches. We filled the shower using water from the bathroom sink faucets. This did not reproduce the leak. We then poured water onto the built in tile seat in the shower directly above where the leak has been occurring. This recreated the leak. This is not a plumbing failure, but a failure of the tiling and liner located on the built in shower seat.