Reopening:  Mold Testing

Mold Grows in Inactive Water and Air Systems

Businesses that are reopening after a temporary shutdown of their facilities should check for microbial contamination to ensure the safety of returning occupants.

According to the CDC, mold and Legionella are the two most  common microbial contaminants that could pose health issues after a shutdown.  The CDC recommends checking for both before reopening a building after an extended period of inactivity.


Purity Laboratories (Purity) offers both a swab test for the presence of mold that can be used on surfaces such as wallpaper, carpet, drywall or furniture and a water test for mold, which can develop when water systems have standing water for extended periods.


Purity currently offers third party testing for Legionella and will begin in-house testing for Legionella soon. 


Why is it important to test for mold when reopening?

When buildings are shut down and water use is reduced, there is an increased risk of water quality issues within the building's plumbing system and associated equipment such as cooling towers, pools, fountains, hot tubs or other equipment.  In addition, heating, ventilation and air conditioning systems (HVAC) that are designed to control humidity and mold are also affected.  When a buildings's HVAC system is shut down, uncontrolled humidity, especially in warm or hot climates, can accelerate mold growth.  Other conditions such as moisture, water, dampness and cold can also encourage mold to grow.

What is mold?

Mold is a type of fungus that can be perfectly harmless.  Mold becomes a problem if it grows and remains unchecked and unattended for long periods of time.

What health issues are caused by mold?

Molds cause allergens.  These allergens can cause an allergic reaction, particularly in individuals who have compromised immune systems, asthma and other types of respiratory issues.  Mold exposure can irritate the eyes, skin, nose, throat and lungs both in allergic and non-allergic individuals.

How Purity tests for mold.

Surface Testing:  Purity will provide specialized environmental swabs for surface testing. 

Surface testing can be done by using either a wet or dry swab.  To do a wet test, the swab is exposed to the accompanying buffering solution before testing.  To do a dry test, the swab is exposed to the buffering solution after testing. 

The recommended area for swabbing should be no greater than 5" by 5".  Swabbing is done horizontally then vertically or vice versa over the same area.

The swabs must be kept at refrigerated but not freezing temperatures when shipped back to Purity for analysis.

Purity uses a rapid petrifilm method (official method of analysis #2014.05) to test for mold colony counts.  Results are reported in 1-3 business days after receipt of a sample.

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