Clearance is where a mold job is won or lost reputationally. A clean remediation with a sloppy clearance report leaves everyone exposed, and a clearance written by the firm that did the removal carries a built-in conflict the next reader will spot. This page covers what "passing" actually means and how to document it.
What are the pass/fail criteria for post-remediation mold clearance?
There is no single numeric pass score; clearance is a convergence of checks. IICRC S520 addresses post-remediation verification as the step that confirms the remediation met its objective — the work area is dry, the visible growth and contaminated materials are gone, and the air inside the formerly contaminated space is consistent with a normal indoor environment (IICRC, S520). In practice clearance rests on three legs: a visual inspection finding no remaining visible mold or moisture-damaged material, moisture readings showing the materials are dry, and — where air sampling is used — an indoor result comparable to a same-day outdoor control.
"Pass" is the alignment of those three. A space can fail clearance on any one of them: visible debris left behind, a moisture reading that says the wall is still wet, or an air sample that runs high against the outdoor baseline.
Does clearance have a numeric spore-count threshold?
No, and asserting one is the most common clearance-report error. Neither IICRC S520, the EPA, nor the AIHA Green Book sets a numeric "clearance limit" for airborne spores, because no health-based universal threshold exists. The EPA's remediation guidance frames a successful outcome as the absence of visible mold and the return to normal conditions, not a count crossing a line (EPA, Mold Remediation in Schools and Commercial Buildings).
So when air sampling is part of clearance, the criterion is comparative: the indoor sample should be consistent with the same-day outdoor control in both count and species profile, with no indoor amplification of indicator genera and no indoor presence of organisms like Stachybotrys (AIHA, Recognition, Evaluation, and Control of Indoor Mold). A clearance report that states a sample "passed the limit of X spores/m³" is inventing a standard. The defensible version describes the indoor-to-outdoor relationship and the visual and moisture results together.
Why must clearance be independent of the remediator?
Because the person being graded should not be the person grading. The credibility of a clearance rests on the verifier having no financial stake in declaring the job done. IICRC S520 treats post-remediation verification as a distinct function, and many state mold programs codify the separation directly, barring the same firm from both remediating and clearing the same property. A clearance signed by the removal contractor invites exactly the conflict-of-interest challenge that undermines the report in a dispute.
This is the same assessment-remediation independence that runs through the S520 report requirements. The clearance inspector is, in effect, performing a focused assessment of the post-work condition — and the report should read as an independent verification, not a victory lap.
What goes in a defensible clearance report?
A clearance report documents each leg of the verification with evidence. The visual inspection records that the work area, containment, and adjacent areas show no remaining visible growth or moisture damage, with photos. The moisture readings show the previously wet materials are now dry, with the locations and values. If air sampling was performed, the report presents the indoor results against the same-day outdoor control, identifies the method (commonly direct microscopy per ASTM D7391), and states the comparative interpretation. The conclusion — pass or fail — ties back to those documented findings, not to an asserted threshold.
What makes it survive scrutiny is the same thing that makes any report defensible: every conclusion maps to a recorded observation. MoldMind structures the clearance data — visual findings, moisture readings, and post-remediation sample results — so the pass/fail conclusion is traceable to the underlying evidence rather than smoothed into narrative. See the sample report and the when-each-standard-applies guide for how clearance fits the broader standards map.
Sources
- IICRC, S520 Standard for Professional Mold Remediation — post-remediation verification framework.
- EPA, Mold Remediation in Schools and Commercial Buildings — success defined as no visible mold and return to normal conditions.
- AIHA, Recognition, Evaluation, and Control of Indoor Mold — comparative indoor-versus-outdoor clearance interpretation.