Referral service, not a contractor. Prevent Home Leaks does not perform plumbing, leak repair, or water damage restoration. We may be paid if you hire a provider through a partner link. Always confirm the provider's license and get a written estimate. How this works
Water stain on the ceiling: roof or plumbing?
Clues
- Appears after rain and on the top floor, often near chimneys, vents or valleys: likely the roof or flashing.
- Below a bathroom or kitchen, and grows when fixtures are used: likely plumbing (shower tests).
- Near an air handler or attic unit, worse in hot weather: likely AC condensate.
- On cold exterior ceilings in winter: possibly condensation from poor insulation or ventilation.
What to do
- Photograph it and mark the edge with pencil to see whether it grows.
- If it's sagging, put a bucket below and carefully poke a small hole to drain it. Bulging drywall can give way suddenly.
- Run the meter test to check for a pressurized supply leak.
- Call a plumber or roofer depending on the clues. If materials stay wet, a water damage pro can measure moisture and dry the area.