What a Passing Mold Clearance Actually Looks Like

There is no single number that means "clean." That surprises most people, including some contractors, so it is worth putting first. No federal agency, no state agency in Washington or Idaho, and no ANSI standard publishes a spore count above which a space fails and below which it passes. Anyone who quotes you a universal threshold is either simplifying or bluffing.

What exists instead is a set of criteria, applied together, judged against a same-day reference sample from outdoors. A clearance passes when the remediated area is visibly clean, the materials are dry, the containment did its job, and the airborne fungal profile inside is consistent with or cleaner than the air outside on that day. Miss any one of those and the result is a fail regardless of how good the others look.

This page walks through each criterion the way we actually apply it, and then covers what happens when a job does not pass.

Criterion one: the visual inspection

The visual comes first and it fails more jobs than the lab does. If there is remaining growth or remaining in-scope material in the work area, there is no reason to spend money on air samples. We stop, document, and tell the contractor what to fix.

What we are looking at:

Remaining visible growth. Any surface in the work area. Framing, sheathing, subfloor, joists, band board, the underside of the decking, the backside of anything that was partially removed.

Remaining in-scope materials. Porous and semi-porous material the protocol called for removing. Drywall, insulation, carpet pad, particleboard, contaminated wood. A common miss in this region is fiberglass batt in a crawlspace: the visible face gets pulled, the fallen batting under the vapor barrier does not.

Cleaning quality. Framing should be cleaned, not just sprayed. We are looking at whether HEPA vacuuming and damp wiping actually happened, particularly on the top edges of joists and plates where dust settles and nobody looks.

Debris and settled dust. Horizontal surfaces above eye level are where this hides. Demolition throws a great deal of material into the air. If it settled and was not removed, it re-aerosolizes the moment containment comes down and the HVAC runs.

Staining. Residual staining is not automatically a fail. Old, dead, cleaned growth leaves a stain that is ugly and biologically inert. Whether it is active is a question a tape lift answers, not one we guess at.

Note what is not on that list: we are not judging craftsmanship, and we are not looking at areas outside the defined work area unless the scope says to.

Criterion two: the containment

Containment is part of what we verify, not just the backdrop we verify inside of. A perfectly clean work area inside a containment that failed is a different result than a clean work area inside a containment that held.

We check poly integrity, taped seams, sealed penetrations at pipes and ducts, HVAC isolation, whether negative pressure is running and confirmed, whether air filtration devices are still operating, and whether a decontamination chamber was built where the protocol called for one.

The single most important thing a contractor can do to protect a clearance result is leave containment up until we have sampled. Once it comes down, the air in the room mixes with the rest of the house within minutes. A sample taken after that characterizes the whole building, cannot rule out cross-contamination during tear-down, and is far harder to defend if the job is contested. If a contractor pulls containment before clearance, we write that the verification was limited, because it was.

Criterion three: air samples against an outdoor control

This is the part most homeowners have never had explained, and it is the part that makes the whole thing coherent.

Outdoor air always contains mold spores. Every day, in every climate, in every season. It is a normal component of outdoor air the same way pollen is. Spore counts outdoors in the Spokane and Coeur d'Alene area swing enormously across the year, from tens of thousands per cubic meter on a warm dry day when leaf litter is being disturbed, down to very low counts in February under snow cover.

Which means an indoor number by itself tells you nothing. Consider two identical lab reports showing 900 spores per cubic meter of Cladosporium inside a remediated crawlspace. In August, with an outdoor control at 8,000, that indoor result is dramatically cleaner than the air outside and passes easily. In January, with an outdoor control at 120, that same indoor number is roughly eight times the reference environment and fails. Same number. Opposite conclusion. The variable that decided it was the outdoor control.

So every clearance we do includes an outdoor control sample, collected the same day, upwind of the structure, on the same calibrated equipment. It is not an upsell and it is not optional. A clearance report with no outdoor control is a page of numbers with no meaning attached, and you should not accept one from us or from anybody else.

What "elevated" actually means

We evaluate three things in the comparison:

Total count. Indoor total should be at or below the outdoor total. Higher indoor totals inside a containment that has been HEPA filtered for days is a signal that something in the space is still producing spores.

Genus profile. This carries more weight than the total, and it is where the interpretation lives. Outdoor air here is normally dominated by Cladosporium, Basidiospores and Ascospores, with Alternaria and Epicoccum seasonally. Finding those indoors at or under outdoor levels is expected. The genera that matter are the water damage indicators: Stachybotrys, Chaetomium, Ulocladium, and Aspergillus/Penicillium at levels well above outdoor. Those spores are not blowing in through a crack. Stachybotrys in particular is heavy, wet and poorly aerosolized. If it shows up inside a cleaned containment and is absent outdoors, something in that space is still growing or was disturbed and not captured.

Hyphal fragments. Elevated fragment counts indicate physically disturbed growth. Fragments do not travel far. They point at the room they were found in.

A brief note on health, because Stachybotrys gets talked about carelessly: CDC's position is that a causal link between Stachybotrys and serious illness has never been established, and there is no diagnostic test that connects a specific mold to a specific set of symptoms in a person. What is documented is allergic response, asthma triggering and upper respiratory irritation in sensitive people, plus genuine infection risk in the severely immunocompromised. We report what the lab found. We do not tell you what it will do to you, because nobody honestly can.

Criterion four: moisture

Air can be clean today and the assembly can still be wet. Wet wood grows mold again, usually within days, and a clearance that ignored moisture content is a clearance that will be wrong by the time the drywall goes back on.

We take pin and pinless meter readings on framing, sheathing and subfloor, and we reference them against a dry standard taken from unaffected material of the same species and dimension elsewhere in the same structure. That reference matters. There is no universal moisture percentage that means dry, because it depends on the material and the season. What matters is whether the previously wet material has come back to the same moisture content as material that was never wet.

We also record temperature, relative humidity and dew point inside and outside the containment. A drying setup running at high humidity inside containment is moving water around rather than removing it, and that shows up in psychrometrics before it shows up anywhere else.

What happens on a fail

A fail is data, not a verdict on the contractor. Restoration crews work in crawlspaces, attics and burned-out basements, and things get missed. The useful question is what specifically failed and what fixes it.

The report names the criterion, the location, and the evidence. Then the correction happens, and we re-test.

The re-test is the same site visit at the same price. Our partner rate is $375 flat for up to three samples, additional samples $100, rush 24 hour lab $100, and a re-test after correction is billed at $375 again. We do not price a failure higher than a pass, and we have no remediation division that benefits from a fail. A homeowner mold inspection, which is a different service, is $425 including one indoor sample plus an outdoor control.

Frequently asked questions

How many samples does a normal clearance need? Two on a standard single-containment residential job: one inside the containment, one outdoor control. Multiple separate containments need one inside each, plus the single outdoor control. Three samples are included in the flat rate.

Can a clearance pass with visible staining still present? Yes, if a tape lift confirms the staining is inert residue rather than active growth, and if the rest of the criteria are met. Stains are cosmetic. The contractor should tell the homeowner that in advance so it does not come as a surprise.

Why not just test before and after and compare? Because pre-remediation conditions are irrelevant to whether the area is clean now. A 90% reduction from a badly contaminated starting point can still be a fail. The comparison that matters is against outdoor air, not against how bad it used to be.

Does a pass guarantee the mold will not come back? No, and we will not write that it does. A clearance says the area met the criteria on the day it was tested. If the water source that caused the problem was not permanently fixed, the mold returns. That is a plumbing, grading or ventilation question, and we say so in the report when we see it.

Is any of this legally required in Washington or Idaho? No. Neither state licenses mold assessment or remediation, and neither requires clearance testing. Carriers, property managers, buyers and attorneys require it constantly. New York's Labor Law Article 32 goes further and bars one company from both assessing and remediating the same job. Washington and Idaho leave that to the contractor's judgment.

Get a clearance done right

If you want a clearance report that holds up, it needs a visual, a containment check, moisture verification, and air samples judged against a same-day outdoor control by somebody with no financial stake in the answer. That is the whole job.

Call to schedule clearance testing in Spokane County or Kootenai County.