If you've recently received a mold inspection lab report for your home or business, you may be looking at a chart filled with terms like Aspergillus, Cladosporium, and "spores per cubic meter." But what does it all mean—and more importantly, how should you respond?

At Bay Area Mold Pros, we provide expert mold testing and mold inspection throughout San Francisco, San Mateo, Santa Clara, Marin, Alameda, and Contra Costa counties. As part of our process, we deliver lab-certified reports that include mold spore counts, species identification, and actionable recommendations. This article will help you understand what those spore counts mean and why they matter.

What Are Mold Spore Counts?

Mold spore counts refer to the number of mold spores found in a specific volume of air, typically measured in spores per cubic meter (sp/m³). These counts come from air samples collected during your inspection and are analyzed by an accredited laboratory.

The lab compares indoor air samples to outdoor “baseline” samples to determine whether the spore concentration inside is elevated—which may indicate a hidden mold source.

Why Spore Counts Matter

Not all mold is visible. Spore counts provide a quantitative snapshot of what's floating in the air you and your family—or your employees—breathe every day. Elevated spore counts can:

• Trigger allergies, asthma, and respiratory problems


• Suggest the presence of hidden mold growth


• Affect indoor air quality and safety


• Help determine the urgency of remediation

Understanding these numbers is essential for making informed decisions about mold removal, air purification, or further inspection.

Common Mold Types in Lab Reports

Here are a few of the mold types you may see in your report—and what their presence could mean:

• Aspergillus/Penicillium: Common indoor molds. High levels often indicate indoor growth due to leaks or poor ventilation.


• Cladosporium: Frequently found on wood and textiles; may not always be toxic but can aggravate asthma.


• Stachybotrys ("black mold"): Often found in water-damaged areas; associated with more serious health effects.


• Chaetomium, Fusarium, Alternaria: May point to chronic moisture issues and structural mold.

Each mold type varies in toxicity, allergenicity, and source, so it’s critical to rely on professional interpretation.

What’s Considered a “Normal” Mold Spore Count?

There’s no universal “safe” level of mold spores, but a general guideline is:

• Low (Normal): Similar or lower than outdoor baseline


• Moderate (Concerning): Elevated levels of common indoor molds


• High (Action Recommended): Elevated levels of problematic species or significantly above outdoor baseline

Keep in mind: even low counts of toxigenic molds like Stachybotrys may require remediation, depending on the species and occupant sensitivity.

How Bay Area Mold Pros Helps You Interpret Results

We don't just hand you a report—we walk you through it.

• Explain what each spore count means


• Identify likely mold sources based on test results


• Recommend targeted remediation or moisture correction


• Provide referrals if needed (we are an independent mold testing company with no financial interest in remediation)

Our certified mold inspector Rick Bruce ensures you get clear, unbiased information to make confident decisions about your indoor environment.

Serving Families and Businesses Across the Bay Area

Whether you're a homeowner concerned about your child’s asthma or a property manager overseeing a commercial space, understanding your mold report is essential. We serve:

• San Francisco


• San Mateo


• Santa Clara


• Marin


• Alameda


• Contra Costa

Schedule Your Mold Testing Today

Still unsure about your spore counts? Let us help you make sense of your indoor air quality.

Contact Bay Area Mold Pros today at (650) 762-6228 or

Visit bayareamoldpros.com to request a professional mold inspection and receive a clear, certified mold lab report—with expert guidance every step of the way.