Black Mold: What It Actually Is, and What To Do About It

Published by Water Damage Restoration Specialists of San Antonio · Last updated 2026-07-25

"Black mold" usually refers to Stachybotrys chartarum, and it has acquired a reputation somewhere between a health hazard and a horror film. The reality is more mundane and, in one specific way, more useful to know.

Color is a poor guide

Many harmless molds are dark. Some problematic ones are not black at all. You cannot identify a species by looking at it, and neither can a contractor — which is precisely why identification is done by an assessor with sampling rather than by eye on a doorstep.

What actually matters for deciding what to do is not the color but two other things: how much there is and what is keeping it wet. A significant area of any indoor mold growth warrants professional handling. A small patch with a known, fixed moisture source usually does not.

Health effects, stated honestly

Mold exposure can cause respiratory irritation, congestion and eye or skin irritation, and it can worsen asthma and allergic conditions. People who are immunocompromised, elderly, very young or have existing respiratory disease can be affected more severely.

Whether a specific health problem you are experiencing is caused by mold in your building is a medical question, and it needs a doctor rather than a restoration contractor. We will not tell you what your symptoms mean, and you should be wary of any contractor who does — it is outside their competence and it is often a sales technique.

Who should be doing this work

Before you let anyone begin, ask what qualifications they hold for mold work specifically — it is a different skill set from general water drying — and ask to see documentation. Look at it properly. Do that with us and with every other company that quotes you. Whether you ask is entirely at your discretion, but it is your home and it is a reasonable thing to want to know.

Keep diagnosis and removal separate where you can. The party finding the problem should not be the only party confirming it is gone. If a company wants to test your home, quote for removing whatever it finds, and then sign off its own work, that is worth a second thought.

What proper remediation looks like

Independent assessmentAn independent party determines the extent and sets the protocol.
ContainmentThe area is sealed and held under negative air pressure so removal does not distribute spores through the rest of the building.
HEPA air filtrationRunning throughout the work, scrubbing airborne spores.
Controlled removalAffected porous material removed and bagged inside containment; non-porous surfaces cleaned and treated.
Moisture correctionThe water source is found and fixed — without this the mold returns and everything before it was wasted.
Independent verificationThe assessor confirms the protocol was met before rebuilding.

What not to do

Do not disturb a large area without containment — it can expose you to far higher spore concentrations than the intact growth did
Do not just bleach it — on porous material bleach adds water and leaves the colonized material behind
Do not paint over it
Do not run fans or the HVAC in an affected area — it distributes spores throughout
Do not ignore the source — removal without correcting the moisture just resets the clock

See our mold remediation service and cost guide for more on what the work involves and what drives the price.

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Need help with this?

We provide water damage restoration, mold remediation and fire damage restoration across all 58 San Antonio ZIP codes, 24 hours a day. Call (844) 476-1017.

Ask to see credentials — from us or anyone else

Before any technician starts work on your property, you are entitled to ask them who they are and what qualifications they hold, and to ask to see documentation. That applies to us and to every other contractor who knocks on your door. Ask at your own discretion, take your time, and do not feel awkward about it — a crew that is happy to be asked is the kind you want in your house. If anyone refuses or rushes you past the question, treat that as your answer.