How to choose a mold remediation company, and questions to ask

Do you need a mold remediation company at all?

Not always. EPA says that if the moldy area is less than about 10 square feet, in most cases you can handle the job yourself. That’s roughly a 3-foot by 3-foot patch.

Hire a professional when the area is larger, when the water was sewage or floodwater, when mold is in the HVAC system, or when someone in the home has health conditions that make exposure riskier. EPA’s own remediation guide treats 10 to 100 square feet as a medium job needing at least limited containment and more respiratory protection, and over 100 square feet as a large job needing full containment.

Your state may also decide for you. Florida and New York license mold work above 10 square feet, Texas at 25 contiguous square feet, and Louisiana when the job exceeds $7,500. In those states, a large job means a licensed professional, and you should verify the license before work starts.

A remediation company’s job is to remove mold safely and keep it from spreading. It should not be the one deciding how big the problem is, and it should not be the one declaring the job done. That’s where an assessor comes in.

If you’re not sure whether you’re facing removal or full remediation, start with mold removal versus remediation. For the bigger hiring picture, see the hire-a-pro hub.

Why should the assessor be independent?

A mold assessor inspects, finds the moisture source, measures the affected area and writes a remediation plan. The remediator carries out that plan. When one company does both, it decides how much work it gets paid for.

Three states address this in law:

Florida’s DBPR adds that holding both licenses does not remove the restriction.

Elsewhere, no law may require it, but the logic is the same. Hire the assessor first, and hire one who has no stake in the cleanup. Our guide to mold assessors versus remediators covers what each role does.

What should a good remediation plan include?

New York’s Department of Labor publishes one of the clearest lists of what an assessor’s plan must cover. It’s a useful checklist in any state:

• Rooms and areas affected.
• Estimated quantity of material to clean or remove.
• Cleanup methods for each area.
• Containment, where needed.
• Protective equipment for workers.
• Clearance procedures and criteria.
• Occupant notice, for occupied homes.
• Cost and time estimates.
• Any disinfectants or coatings to be used, with attention to occupant sensitivities.
• The underlying moisture source and the type of contractor who can fix it.

The remediator then writes a work plan that carries out the assessor’s plan. In New York, you get that work plan before work begins.

Note the last item. New York’s definition of mold remediation does not include fixing the moisture source. Someone still has to fix the leak. Make sure the plan says who.

Questions that expose a bad mold remediation company

Ask these before you sign. The answers tell you more than a sales pitch.

1. “Who did the assessment, and do you have any business tie to them?” In Florida, Texas and New York, the honest answer is a separate firm.
2. “What is your state license number?” In Florida, ask for the individual’s license, because DBPR licenses individuals, not businesses.
3. “Where is the moisture coming from, and who is fixing it?” If they don’t know or don’t care, mold will return.
4. “How will you contain the work area?” For anything beyond a small patch, expect plastic sheeting and negative air pressure with HEPA filtration. EPA’s guide calls for containment on medium and large jobs.
5. “What will you remove, and what will you clean?” Porous materials like soaked drywall and carpet pad are generally removed. Watch for a plan that relies on spraying chemicals instead of removal.
6. “Who does the clearance test?” The right answer is the independent assessor.
7. “Will you take down containment before clearance?” The right answer is no.
8. “What happens if the area fails clearance?” Get re-cleaning terms in writing.
9. “Can I see proof of insurance that covers mold work?” Florida requires licensed remediators to carry at least $1,000,000 in general liability with specific mold coverage, according to DBPR.
10. “What do you need from me for the insurance claim?” A good company documents its work. It does not tell you what your policy covers.

For general warning signs that apply to any restoration contractor, see restoration scams and red flags.

Red flags in a mold remediation quote

Get at least two written quotes based on the same assessor’s plan so you’re comparing like with like.

What should mold remediation cost?

Published averages vary by source. Fixr puts the average at about $3,500. Bob Vila, drawing on Angi, HomeAdvisor and Fixr data, puts it at about $2,254. Small, contained jobs cost much less. Whole-house or HVAC jobs cost much more.

The more useful check is the quote itself. It should list containment, HEPA air filtration, removal and disposal of materials, cleaning, and clearance testing as separate lines. Rebuilding, such as new drywall and paint, is often a separate contractor and a separate bill.

Our mold remediation cost page compares five published sources side by side and shows what should be on the quote.

How do you know the job is done?

The job is done when an independent assessor says it passed, in writing. EPA describes success as a fixed moisture problem, no visible mold, mold-damaged materials or moldy odors, and, if samples were taken, indoor mold levels similar to outdoors.

In New York, the contractor may not dismantle containment until you have a passed clearance report. In Texas, the licensed remediator must give the owner a Certificate of Mold Remediation within 10 days of completion.

Hold the final payment until you have that report. Our page on mold clearance testing explains what passing looks like and how to read the results. To check whether your state requires a license, see mold licensing by state.