Overview
In a competitive South Bay market, it's easy to fall for a home and overlook red flags. But past or hidden water damage can mean expensive repairs and lingering mold after you've signed. Here's how to spot the warning signs during a showing - before it becomes your problem.
Look up: ceilings
Scan ceilings for stains, discoloration, or fresh patches of paint that don't quite match - sometimes a sign that a stain was painted over rather than the leak fixed. Pay attention to areas under bathrooms and around skylights.
Look down: floors
Watch for cupping or warping in hardwood, lifting laminate, soft spots, or tile that sounds hollow when tapped (possible substrate moisture). Be wary of an isolated patch of brand-new flooring.
Look at the walls
Bubbling or peeling paint, water stains near baseboards, and warped trim suggest moisture. Run your eyes along the bottom of walls in lower-level rooms.
Use your nose
A musty or damp smell - especially in basements, closets, crawl spaces, or rooms that have been closed up - is one of the most reliable clues to hidden moisture or mold, even when nothing is visible. Be skeptical of heavy air fresheners masking an odor.
Check the usual suspects
- Under sinks (kitchen and bathroom) for stains, rust, or warping.
- Around windows and doors for water intrusion signs.
- The base of the water heater and around appliances.
- The roofline and attic, if accessible, for stains on rafters.
Consider the location
Ask whether the home is near a creek or in a low-lying area. In parts of the Peninsula, for example, homes near San Francisquito Creek have a documented flood history. Local flood context matters.
Get a professional assessment
A standard home inspection helps, but if you see or smell warning signs, a specialized moisture/mold assessment can confirm whether there's an active or past problem - using moisture meters and thermal imaging. It's far cheaper to know before you buy.