How to Keep Your Apartment Healthy

Mold growth is always caused from too much water or humidity inside a living space.

Reasons for high humidity:

  • water leaks
  • no or low performing exhaust fans
  • single paned or broken windows
  • no insulation in perimeter walls 
  • too many people or contents in a small space

Water leaks

Please contact your landlord or property management team as soon as possible, even if it is after business hours. The sooner the leak can be stopped, water removed, and professional drying started; the less chance mold will grow from the leak. Everyone wins this way.

Tenants may also want to consider renters insurance. There are times when tenents may have to pay out of pocket and wait to recover. 

No or low performing exhaust fans

The reality in San Francisco is exhaust fans aren’t always possible in many of our beautiful historic buildings. If you don’t have a bathroom exhaust, please do leave a window open after a bathing.  If your exhaust fan seems weak, take a piece of toilet paper and see if the fan will hold the toilet paper next to the vent when it’s turned on. If it doesn’t pass the test, you may choose to discuss this with your landlord. Exhaust fans can prevent water damage to the building in bathrooms.


Single pane windows can create interior condensation. It is usually time and cost prohibitive to replace historic windows in San Francisco. By working together landlords and tenants can reduce mold growth by leaving breathing space between furniture and windows/walls. Store clothing and shoes in sealed, plastic containers when possible. For instance, if you store your party shoes under your bed without putting them in a plastic box, you may have mold growth on your shoes. Do not store items in cardboard boxes – mold loves cardboard.

No insulation in perimeter walls and floors

Again, this is one of those things that tenants and landlords need to work together to reduce interior damage. A simple humidity gauge will tell tenants when it’s time to turn on exhaust fans or open windows. Any time the humidity is greater than 52% it’s time to get some fresh air inside. 

Too many people or contents

San Francisco has very high rents. This means more people living in smaller spaces. Turn the exhaust fans on if there a lots of people using the kitchen and bathroom. Or open the windows.

Tenants may need to rent storage for excessive contents. Definitely store all clothing, paper, and shoes in sealed plastic containers.

A “light” remediation

A “heavy” mold remediation