A visible patch bigger than a couple of square feet isn’t a bleach-and-forget situation — that’s a call. But you don’t need to see mold to have a problem. A musty smell that won’t leave a bathroom, crawl space, or laundry area usually means something is growing where you can’t see it. If you’ve had headaches, worsening allergies, or a cough that goes away when you’re out of the house, elevated spore counts are worth ruling out. Same goes if an air quality test already came back high.
Santa Ana’s climate is deceptive about this. People assume mold is a wet-climate problem, but the moisture swings here — the marine layer, the coastal humidity, and then the dry heat that hits during Santa Ana wind events — stress building materials in ways that invite moisture intrusion. Older stucco homes throughout the area are particularly vulnerable. Water works in around windows, through wall cavities, along slab edges. By the time you smell it, it’s usually been growing for a while. The longer it goes, the worse the job gets.