Quick test
- Efflorescence is crystalline and powdery, and dissolves in water.
- White mold is fuzzy or cottony, and often grows on wood, drywall, or stored items.
- Efflorescence on concrete is common; mold on concrete usually grows on dust or organic residue.
- Both mean water is moving through or onto the wall.
What efflorescence tells you
Water moving through concrete or block carries minerals to the surface, then evaporates and leaves salts behind. It isn’t harmful itself, but it’s a sign of moisture — often from grading, gutters, or sprinklers. See sprinkler leaks and foundation cracks.
When it’s more likely mold
- Fuzzy texture that smears rather than crumbles
- Growth on wood framing, drywall, cardboard, or carpet
- A musty smell
- Spots that spread or change color
What to do
- Brush efflorescence off dry and fix the outside drainage.
- If it might be mold, don’t scrub dry — see small mold cleanup.
- Check humidity in the basement.
- Call for an inspection if you’re unsure or the area is large.
Vault’s AMRT-certified crew performs post-remediation clearance; air samples go to Sporecyte, an outside lab. Inspections start at $99; remediation starts at $500.
Not sure what it is?
Call (385) 250-2825 — answered live 24/7 by the Vault crew.
In Provo? See mold remediation in Provo for inspection pricing ($99, $199 or $349) and how a job runs.