What should I do about a ceiling leak or water stain?

Treat a growing ceiling stain or dripping water as a reason to investigate promptly, not proof of a plumbing leak. Roof damage, condensation, an upstairs fixture or a hidden supply line can look similar from below. Keep clear of sagging drywall, and avoid lights or electrical fixtures near active water. If you can safely stop an affected fixture or shut off the home's water, do so; never risk reaching a valve near exposed electricity. Take photos and note whether dripping follows rain or indoor water use. A plumber can check plumbing sources, while a roofer or other specialist may be needed if the cause is elsewhere.