Most Likely Causes (Ranked)
Water enters through damaged shingles or flashing, travels along rafters 10-15 feet before dripping through ceiling.
Bathroom, washer, dishwasher, or water heater on floor above.
Clogged condensate drain overflows pan. #1 ceiling leak cause in summer.
Escaping attic heat melts snow; meltwater refreezes at eaves, backs under shingles.
Poor ventilation + moisture = condensation on roof sheathing dripping through ceiling.
How to Fix It
Emergency Management
Free- 1Bucket under drip. Poke hole in bulging ceiling to release water.
- 2Move furniture/electronics. Turn off water if plumbing source.
- 3Run dehumidifiers.
Trace Roof Leak
$150-1,000+- 1Attic inspection: trace water trail with flashlight.
- 2On roof: check 10-foot radius uphill for damaged shingles, failed flashing, cracked vent boots.
- 3Temp: roofing tar from inside. Perm: replace damaged materials.
Clear AC Condensate
$0-200- 1Wet/dry vacuum on exterior drain outlet.
- 2Monthly vinegar down clean-out port.
- 3Install safety switch ($15-30).
When to Call a Professional
Bulging ceiling can collapse — relieve pressure by poking drain hole.
Sudden heavy leak (not rain) = possible burst pipe. Shut off main water.
Ceiling water + electrical = electrocution risk. Turn off breaker.
Mold starts in 24-48 hours.
How to Prevent It
Inspect attic twice yearly.
Maintain AC condensate lines monthly.
Ensure exhaust fans vent outside (not into attic).
Maintain R-38+ attic insulation in cold climates.
Frequently Asked Questions
Plumbing leak above, AC condensate, or attic condensation. Check if below bathroom/kitchen/AC.
AC drain: $0-200. Roof patch: $150-500. Plumbing: $100-400. Drywall: $200-500.
Yes if wet 24-48+ hours. Small areas: bleach solution. 10+ sq ft: professional remediation.
Use stain-blocking primer first (Kilz/Zinsser). Only after fixing the leak and drying fully.