Start with safe, visible clues
A roof leak can begin far from the stain you see indoors. Check the attic from a stable surface during daylight for damp insulation, discolored wood, or visible daylight. Outside, look from the ground for displaced shingles, damaged flashing, or debris in gutters.
When to call a professional
Do not climb onto a wet, steep, damaged, or unfamiliar roof. Active leaks, sagging areas, storm damage, and electrical-adjacent water intrusion should be assessed by a qualified roofing professional.
Related: roofing terminology and our troubleshooting guides.