Black Mold Facts: What It Is, What Texas Rules Say and When to Call a Pro
"Black mold" is one of the most searched mold terms there is, and one of the most misunderstood. This guide sticks to what official sources and Texas law actually say, for homeowners and renters in Corpus Christi, TX and the Coastal Bend. It makes no health claims. If anyone in your home has symptoms, talk to a doctor, and see the consumer mold pages published by EPA (epa.gov/mold) and CDC for general guidance.
Corpus Christi Mold Remediation is a free quote service, not a mold company. You describe the problem once, and independent mold inspection and remediation companies may reply with quotes. Some of those companies may pay to receive requests, and they reply on their own schedules.
What people mean by "black mold"
"Black mold" is a popular name, not a test result. It is often used for Stachybotrys; cost guides such as Fixr list "black mold (Stachybotrys)" as its own category. But the color of a spot on a ceiling does not tell you the species. Identifying a species takes a sample and lab analysis, and in Texas collecting or analyzing a mold sample for hire is mold assessment under Occupations Code §1958.001.
Does the species change what you should do?
Usually not. TDLR's FAQ says: "Generally, it is not necessary to identify the species of mold growing in a residence," and "testing to determine what kind of mold is present is not required prior to remediation or cleaning." The response is the same whatever the color: stop the water, then clean or remove the growth in a way that fits the size of the job.
Texas law follows the same logic. The licensing threshold in §1958.102 is written in terms of the surface area affected, 25 contiguous square feet, and the statute text does not single out any species.
Black mold myths and facts
- Myth: you need to know the species before cleanup. Fact: TDLR says species testing is not required before remediation or cleaning.
- Myth: any black spot needs a licensed company. Fact: under 25 contiguous square feet, a homeowner can clean it or hire anyone. Licensing applies to hired work at 25 square feet or more.
- Myth: Texas does not license mold companies. Fact: TDLR licenses mold assessors and mold remediators under Occupations Code Chapter 1958. Texas requires TDLR licenses for mold assessment and remediation work on 25 or more contiguous square feet (Occ. Code §1958.101–.102). Verify any company at tdlr.texas.gov/LicenseSearch.
- Myth: one company can test it and then remove it. Fact: In Texas, the company that assesses your mold and writes the protocol cannot be the company that removes it on the same project, and one owner can't hold both (Occ. Code §1958.155).
- Myth: removing the mold solves the problem. Fact: the moisture source has to be fixed too. On licensed jobs, the assessor marks the certificate when "the underlying cause of the mold has been remediated so that it is reasonably certain that the mold will not return from that remediated cause" (§1958.154(a)).
Why black spots show up in Corpus Christi homes
Mold needs moisture, and the Coastal Bend supplies it. NOAA's 1991–2020 normals for Corpus Christi International Airport show about 32 inches of rain a year, September the wettest month, about 123 days a year at 90°F or hotter, and summer dew points averaging about 74°F. As general building science, surfaces cooler than the dew point collect condensation, so AC vents, ducts in hot attics and bathroom ceilings near the exhaust fan are common spots.
EPA's moisture guidance is widely cited for keeping indoor relative humidity below 60% (ideally 30–50%) and drying wet materials within 24–48 hours. Check epa.gov/mold for the current wording. For ceiling spots, see our bathroom and ceiling mold guide.
What to do when you find it
Find and stop the water
A roof leak, an AC drain, a plumbing drip or shower steam with a weak fan. Cleaning without fixing the source tends to bring the spots back.
Estimate the area
A patch of about 5 by 5 feet is 25 square feet. Add up connected areas, including what may be behind the surface.
Small and visible: decide whether to do it yourself
Under 25 contiguous square feet, Texas lets owners and tenants clean it themselves or hire anyone. If the cleanup uncovers more mold that brings the total to 25 square feet or more, the unlicensed exemption no longer applies (16 TAC 78.30).
Larger or hidden: start with a licensed assessor
The assessor writes the protocol. A separate licensed remediator does the work. Our mold removal guide explains containment and the steps.
Keep the paperwork
Ask for the Certificate of Mold Damage Remediation (TDI form MDR-1). Insurers can't make underwriting decisions based on remediated mold damage when you have it (Ins. Code §544.303), and you must give buyers copies from the last five years (§1958.154(b)).
The 25 square foot line: Under 25 contiguous square feet, a homeowner can clean it themselves or hire anyone. At 25 sq ft or more, hired work needs licensed companies, a written protocol, a work plan, TDLR notification (5 days ahead, or the next business day in a water-damage emergency), a clearance assessment, and a Certificate of Mold Damage Remediation within 10 days.
How much does black mold removal cost?
Fixr's published national estimate for black mold (Stachybotrys) removal is $800–$7,000 (Aug 2025). The same source puts overall mold remediation at $1,500–$9,000, and This Old House (Mar 2026) gives $10–$25 per square foot. These are published national estimates, not quotes. Quotes come from independent companies, not this site.
| Item | Typical range | Source |
|---|---|---|
| Black mold (Stachybotrys) | $800–$7,000 | Fixr |
| Bathroom | $500–$1,500 · $500–$1,000 | Fixr · This Old House |
| Per square foot | $10–$30 · $10–$25 (avg ≈ $18) | Fixr · This Old House |
| Mold inspection (standalone) | $450–$800 | Fixr, Jan 2025 |
Published national estimates, not quotes (Fixr, Aug 2025; This Old House, Mar 2026). Quotes come from independent companies, not this site.
The full table and a calculator are in our mold remediation cost guide for Corpus Christi. If you are weighing a lab test, read do you need mold testing? first, or see mold inspection and testing.
When you want quotes, describe the problem once or call (361) 247-3040.
Frequently asked questions
Is black mold more dangerous than other mold?
This site does not make health claims or give medical advice. TDLR says it is generally not necessary to identify the species of mold growing in a residence, and the cleanup approach is the same whatever the color. For health questions, see EPA and CDC consumer guidance on mold and talk to a doctor.
Do I need to test black mold before removing it?
Not usually. TDLR says testing to determine what kind of mold is present is not required before remediation or cleaning. For jobs of 25 contiguous square feet or more, a licensed assessor still inspects and writes a protocol, and a separate licensed company does the removal.
Can I remove black mold myself in Texas?
Under 25 contiguous square feet, Texas lets a homeowner clean it themselves or hire anyone. At 25 square feet or more, hired work needs TDLR-licensed companies, a written protocol, a work plan, TDLR notification, a clearance assessment and a Certificate of Mold Damage Remediation within 10 days.
How much does black mold removal cost?
Fixr's published national estimate for black mold (Stachybotrys) removal is $800 to $7,000 (Aug 2025). Size, location and how much material comes out drive the price. Quotes come from independent companies, not this site.