What is the mold remediation process per the S520 standard?
The mold remediation process under the ANSI/IICRC S520 standard is a documented sequence: assess the contamination, contain the work area to stop spores from spreading, establish negative air pressure and filtration, physically remove the mold and the materials it has colonized, clean and HEPA-vacuum the space, then verify the result with independent testing before the area is cleared. The guiding principle is simple: mold is removed, not painted over or killed in place, and the job is finished by proof, not by opinion.
That standard is not an abstract reference to us. Mold Eliminators founder Craig Herrmann co-authored the ANSI/IICRC S520 standard, the national document that defines how mold remediation is supposed to be done. When we describe the process below, we are describing the rulebook he helped write, applied to your home or building in Las Vegas. You can read more about Craig and his credentials.
What the S520 process actually involves
S520 organizes remediation around a few non-negotiable goals: remove the contamination, protect the people doing the work and the people living in the building, and confirm that the space is genuinely clean at the end. Everything in the process exists to serve one of those goals. Here is what each phase means in plain English.
Assessment first. Before anyone touches the mold, a qualified inspector defines the problem: where the growth is, how far it has spread, what is feeding it, and what materials are affected. This is also where the moisture source is identified, because remediation that does not fix the water cause is remediation that fails. The on-site inspection we provide for property owners is free; if you want independent lab analysis of what is in the air or on a surface, that lab testing is a paid add-on, not a hidden upsell baked into the price.
Containment. Mold spreads by spores, and disturbing a colony releases millions of them. S520 calls for sealing the work area with poly sheeting and, on larger jobs, building an airlock so spores cannot drift into clean rooms while the work happens. The bigger or more sensitive the contamination, the more robust the containment.
Negative air and filtration. Inside the containment, air scrubbers with HEPA filtration run continuously and pull the room to negative pressure, so air flows into the work zone and out through the filter rather than escaping into the rest of the building. This is the engineering that keeps a remediation from becoming a contamination event.
Physical removal. This is the heart of S520, and the part many shortcuts skip. Mold is removed physically. Porous materials that have been colonized, such as paper-faced drywall and saturated insulation, are cut out and bagged. Salvageable surfaces are HEPA-vacuumed and damp-wiped. The standard is explicit that you cannot simply spray a biocide on visible mold and call it dead; dead spores are still allergenic, and fogging a wall does nothing for the colony inside it.
Cleaning and drying. Once the source materials are gone, the entire containment is detail-cleaned and HEPA-vacuumed, and any remaining moisture is dried to a normal, documented level so the problem cannot simply regrow. This is where remediation overlaps with water damage restoration, because mold is almost always a moisture problem first.
Verification. S520 finishes on evidence. The space should be visibly clean, dust-free, and dry, and independent post-remediation testing confirms the conditions match a clean reference area. We use an independent third-party lab for that verification rather than grading our own work, so the clearance you receive is genuinely objective. The full sequence is laid out on our process page and our core mold remediation overview.
Need help now?
Talk to a Las Vegas expert
In-house certified crews. One-hour emergency response across the valley, 24/7.
What to do next
If you suspect mold, the right first step is a calm, factual assessment, not a panic purchase. Start with a free on-site free inspection for your property, where a certified technician identifies the growth, traces the moisture source, and tells you honestly whether you have a problem that warrants remediation or one you can handle yourself. We are anti-upsell by design: if you do not need us, we will say so.
If remediation is warranted, you will receive a written scope that follows the S520 sequence above, with the containment, removal, and verification steps spelled out so you know exactly what you are paying for and how the job will be proven complete. Every technician on the crew is a certified W-2 employee, never a subcontractor, so one accountable team owns the work from assessment to clearance. If water is actively spreading or the situation is urgent, our one-hour emergency response runs 24/7 across the Las Vegas valley. Mold Eliminators has served the region since 1996 and remediated more than 255 properties to this standard.
Related questions
- Is killing mold with bleach or a biocide the same as remediation?
- No. S520 is clear that mold must be physically removed, not just killed in place. Dead mold spores are still allergenic, and spraying a surface does nothing about the colony growing inside drywall or insulation. Proper remediation cuts out and bags the colonized materials, HEPA-cleans the space, and corrects the moisture source so it cannot return.
- Is the mold testing free?
- The on-site inspection is free for property owners: a certified technician comes out, finds the growth, and traces the moisture cause at no charge. Independent lab testing and analysis, the kind that puts a number on what is in the air or on a surface, is a separate paid add-on. We keep that line clear so you always know what is included and what is optional.
- How do you know the remediation actually worked?
- The job finishes on evidence, not opinion. After the work, the area should be visibly clean and dry, and an independent third-party lab confirms conditions match a clean reference area before the space is cleared. Because the lab is independent of our crew, the result you receive is objective rather than a contractor grading their own job. See our documentation and insurance claims page for how that record supports a covered claim.
Want it done to the standard Craig helped write? Start with a free inspection.
A free, no-pressure on-site inspection from a certified technician who traces the moisture source and tells you honestly where you stand. One-hour emergency response, 24/7, across the Las Vegas valley. Independent lab verification when you want proof.