ANSI/IICRC S520 is the procedural standard for professional mold remediation, in its fourth edition, published in 2024. The IICRC describes it as covering the principles of mold remediation together with structural remediation, HVAC remediation and contents remediation. It is the document a competent contractor is working to, and the reason a scope looks the way it does.
You do not need to read it. You need three things from it: what its conditions mean, what it says the finish line is, and how to check that the company in front of you is working to it.
The three conditions
| Condition | What it describes | What it usually means on site |
|---|---|---|
| Condition 1 | A normal fungal ecology. | The target. It is what remediation returns an area to, and what verification checks. |
| Condition 2 | Settled spores and fragments. | Surfaces around and beyond the growth, which is why the cleaned area is larger than the visible area. |
| Condition 3 | Actual mold growth. | The material with growth in or on it, which is what gets removed or cleaned depending on what it is made of. |
The useful consequence of that table is the second row. A scope that cleans only the patch you can see has treated condition 3 and ignored condition 2, and the smell usually comes back from the surfaces nobody touched.
What the standard shapes on a real job
- Containment, so removal does not distribute what removal disturbs.
- Negative air with HEPA filtration, so the sealed area draws inward.
- Removal of affected porous material, because growth lives inside those materials rather than on them.
- HEPA vacuuming and damp wiping of what stays, over the condition 2 area.
- Drying, because a remediation ends dry and a space closed up wet is a repeat job.
- Post remediation verification in writing, which is the check that the area reached condition 1.
Not every job needs the full setup. Settled dust in one corner is usually HEPA vacuumed and damp wiped without a barrier. Growth inside a wall cavity is where containment earns its cost.
The other standard in the room
Where water caused the growth, ANSI/IICRC S500 governs the water half. It sorts a loss by category, one to three by how contaminated the water is, and by class, one to four by how much material is wet. It also sets the documentation expectation: readings recorded at each monitoring point on each day the project is active, and photographs that catch the meter reading and the affected material in the same frame.
That matters for a mold job because the category rule is stricter than the growth rule. Porous materials exposed to category 3 water, which includes sewage and ground water, are removed rather than cleaned, whether or not growth is visible yet.
What a technician can hold
The IICRC certifies technicians under named designations. Water Damage Restoration Technician covers water losses, sewer backflows and contamination, and has no prerequisite. Applied Structural Drying is the drying specialization and requires the first. Applied Microbial Remediation Technician covers mold and sewage remediation. Separately, IICRC Certified Firm is a business designation held by a company employing certified technicians, and it can be checked in a public verification lookup.
DHL is IICRC certified, licensed and insured, and family owned since 2010.
What New Jersey licenses
Not mold. New Jersey has no state mold remediation license and the Department of Health publishes guidance and does not license remediators, so no company in this state can be state licensed for mold. Any page that says otherwise is describing something that does not exist.
What the state does require is registration for home improvement work with the Division of Consumer Affairs. The 13 digit number issued, beginning 13VH, must appear in advertising, contracts, business cards, estimates and proposals, and omitting it is its own violation separate from any complaint about the work. The regime is also tightening: the Home Improvement and Home Elevation Contractor Licensing Act was enacted on 8 January 2024 and its education and training requirements took effect on 1 February 2026, with municipalities barred from issuing construction permits to contractors without an active state license.
Reading a quote against the standard
- Does it name containment and negative air, or only cleaning?
- Does it say what happens to the affected porous material?
- Does it cover an area larger than the visible growth, which is the condition 2 work?
- Does it include drying with daily readings, and does it say when drying finishes?
- Does it say what the post remediation verification consists of and who performs it?
- Does it name the water source and who is fixing it?
Six answers, and any competent contractor gives them without hesitating. A quote that is a single line and a total has not been written against a standard at all.
Independence, and where to pay for it
Where a third party result is needed, for a sale, a landlord, a management company or a carrier, independent clearance testing is arranged so the laboratory result does not come from the company that did the removal. Keeping the person who tests separate from the person who removes is worth more to a buyer than any assurance either could write.
The full method is on Mold Remediation, the stage by stage version is in Mold removal in New Jersey, the process step by step, and the water standard side is on Water Damage Restoration.
This article is about Mold Remediation.