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Microbial Growth FAQs

Frequently Asked Questions

What is microbial growth?

Microbial growth, often referred to as mildew or mold, is a family of fungi that is commonly found both indoors and outdoors. Microbial growth indoors occurs when there is high humidity or moisture, low sunlight, oxygen, the right temperature, and organic matter present. Since microbial growth can be found everywhere, and it is constantly reproducing, all of us are exposed from the air we breathe, both indoors and outdoors, daily. Certain buildings depending on their age, size, construction, design and condition can be more prone to microbial growth than others. Leaks, high humidity, and flooding can also lead to the conditions that support microbial growth. Growth can occur on building material in as little as 24 to 48 hours.

Are there health concerns associated with exposure to microbial growth?

Exposure to damp and moldy environments may cause a variety of health effects, or none at all. Some people are especially sensitive to microbial growth. For these people, exposure to microbial growth can lead to symptoms such as stuffy nose, wheezing, and red or itchy eyes, or skin. Some people, such as those with allergies to molds, those who have asthma, or those who are immunocompromised may have more intense reactions.

How can I differentiate between mold, mildew, and dust?

Mold is a fungus that grows in moist areas. Mold has a distinctly unpleasant, musty smell like rotten wood, wet socks, or soggy paper.

Mildew refers to a certain type of mold and is often used to refer to mold growth. Mildew often lives on shower stalls, windowsills, and other places where moisture levels are high.

Dust is dry and has an earthy smell since dust typically consists of dirt, pollen, and soot brought in from outside as well as hair, pet hair, clothing/carpeting lint.

What actions does Boise State take to prevent and respond to environments that can contribute to microbial growth?

The university takes the following actions to manage the opportunity for mold to grow:

  • Housing staff respond to any work requests promptly to inspect and rectify any issues.
  • Boise State works with third party contractors to replace any failing exhaust fans as they are identified.
  • Housing staff replace filters in HVAC and AC units three times a year. This allows proper ventilation throughout the building by ensuring the HVAC system has an unrestricted airflow.
  • Visual inspections of ducts are completed three times a year.
  • Ducts and vents are cleaned once a year by a third party.
  • When microbial growth is found, protocols are in place to remediate the area of concern.

What should I do to help prevent microbial growth in my residence hall?

  • Use bathroom exhaust fans during and for 15 minutes after showering and use kitchen exhaust fans when you are cooking.
  • Avoid taking extremely hot and/or long showers that produce excess steam.
  • Report abnormal humidity, unusual presence of moisture, leaks, or other water related issues, immediately.
  • Keep shower doors or shower liners closed when showering to prevent water from leaving the shower area.
  • Use a bath mat to absorb drips caused when leaving the shower and hang it to dry when finished.
  • Hang towels and wet clothes properly to dry.

What do I do if I suspect mold or mildew in my residence hall?

Microbial growth concerns can be reported to Boise State Public Health at or a message can be left at (208) 426-1523.

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