Typically for California the outdoor spore count can be anywhere from 2,000-5,000 spores for any given time of the year. If your spore count comes back and a bedroom has 10,000 spores while the outside had 2,000 for sensitive people that might be a problem. As the number of spores goes up, more and more people will be affected. Around 20,000 spores it starts to become serious mold problem. There are houses I have seen with 50,000 or 100,000 spores or more! Houses that have a musty mold smell need mold remediation before they are livable. The purpose of a mold inspection is to find the presence of mold; the amount and variety.
The five most common types of mold found in homes are: Aspergillus, Fusarium, Penicillium, Stachybotrys, and Myrothecium.
Mold types have many different varietals, for instance Aspergillus has: Aspergillus candidu, Aspergillus carneus, Aspergillus clavatus,Aspergillus deflectus…. some are more pathogenic than others. Some types of molds produce mycotoxin – a poisonous chemical. The dreaded ‘Black Mold’ that everyone fears is a varietal of Stachybotrys.
During a mold inspection, the inspector also takes moisture readings of all the walls. Moisture level reading of 20%-25% or above are redflags that there is a leak behind the wall.