For licensed inspectors
How to spot water damage in a home inspection
Spot water damage by looking for stains, peeling finish, swollen trim, efflorescence, soft flooring, rust at fixtures, and musty odor—then trace whether the source looks like a roof, plumbing, grading, or condensation, and say when you cannot confirm it is dry today.
Practical signs of water damage inspectors look for: ceilings, windows, bathrooms, basement, and how to photograph and word findings.
What you can see (and smell)
Brown or yellow stains with a drip pattern, peeling paint, bubbling drywall, cupped or stained hardwood, swollen MDF baseboard, rust at supply valves, mineral crust on masonry (efflorescence), and a persistent musty smell. Infrared and a moisture meter help you compare a stain to a dry control area; they do not by themselves prove a leak is active.
Follow water’s path
Ceiling stain under a bathroom: look up at the tub, toilet flange, and supply. Stain along an exterior wall: windows, flashing, and grading. Basement: downspouts, negative slope, and the water heater or washer. Roof-related stains often align with valleys, chimneys, and skylights—confirm from the attic if you enter.
Condensation mimics leaks: unvented baths, dryer ducts that stop in the crawl space, and cold-water pipes in humid air. High-efficiency furnace condensate that is clogged can look like a “mystery puddle” next to the unit.
Active vs. historic
A dry, uniform stain with no elevated meter reading may be old. A cool, dark, elevated reading after rain is more concerning. You rarely can date a stain to the week. Write “stain observed; moisture elevated / not elevated at time of inspection” and recommend monitoring or a contractor when the source is not obvious.
What not to claim
Do not call mold species or say the house is “waterproof.” Do not skip a stain because the seller painted. Photograph with a scale (tape or a tool in the frame), note the location in the section (bath, roof, foundation), and send hidden-cavity questions to opening walls or a specialist. Your job is to flag the pattern so the client can decide next steps.
Common questions
- Is every stain a leak?
- No. Condensation, past repairs that are now dry, and splash from showers all stain. The report should separate observation from the likely source and the limit of a visual inspection.
- Should I use a moisture meter on every wall?
- Use it where you see or suspect moisture, and compare to a similar dry surface. Scanning the entire house is not a typical general inspection.
Is every stain a leak?
No. Condensation, past repairs that are now dry, and splash from showers all stain. The report should separate observation from the likely source and the limit of a visual inspection.
Should I use a moisture meter on every wall?
Use it where you see or suspect moisture, and compare to a similar dry surface. Scanning the entire house is not a typical general inspection.