Short answer
Stachybotrys chartarum produces mycotoxins and is worth taking seriously, but color does not identify a species and many non-black molds affect health. Any indoor growth on chronically wet material should be removed regardless of what shade it is.
Only laboratory analysis identifies what is actually present. Plenty of dark staining we are called about turns out to be Cladosporium or simple soot, and plenty of unremarkable grey growth turns out to be Chaetomium, which indicates long-term saturation.
The practical point: the species changes the urgency of the conversation, not whether the material has to come out.
Why it matters in San Diego
Stachybotrys needs materials soaked for a long time, like drywall behind a slow slab leak or under a leaking window. In San Diego we find it most in inland homes with hidden plumbing leaks and in older homes with roof problems.
Many dark molds aren't Stachybotrys. You can't tell by color — only a lab can.
How we handle it
We treat every significant growth with the same containment and removal, whatever the species. If you want to know what it is, lab testing starts at $195 for 2 samples.
Signs it's time to call us
- Slimy, dark green-black growth on drywall
- A strong musty smell
- Water damage that's been there for weeks
Mistakes to avoid
- Panicking over color alone
- Ignoring 'regular' mold because it isn't black
- Disturbing it without protection
Related questions
Do I need testing to remove it?
No. Removal is the same either way. Testing is helpful if you need proof for a landlord, buyer or doctor.
See our black mold page
We have a full page on black mold removal in San Diego with more detail.