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Mold

Mold is a form of fungi, found in moist indoor and outdoor environments. Although mold exposure does not always cause health problems, daily exposures can trigger asthma and cause respiratory problems, headaches, watery eyes, dizziness, lethargy, and rashes. Learn how to prevent mold or clean it up, and find resources for tenants.

Short URL: kingcounty.gov/mold

Mold prevention

In King County, the wet seasons of fall, winter, and spring can mean more moisture in your home. Too much moisture can lead to mold and mildew. Here are some suggestions to keep your home clear of molds.

icon representing action to dry excess moisture Get excess moisture out of your home

  • Flush the air two or three times a day (for three to four minutes, open all the doors and windows and let fresh air circulate through the home).
  • Ventilate the bathroom and the kitchen with an exhaust fan.
  • Keep shower curtain or bathtub sliding door open after bathing to increase air circulation.
  • Assure that the dryer vents freely to the outside.
  • Heat all the rooms in your home to keep moisture from forming on the walls and other surfaces of unheated areas.

Icon representing warning to prevent a dangerous situation  Stop moisture from coming in

  • Stop any leaks from the roof, poorly-drained gutters and plumbing.
  • Stop water from entering basements and crawlspaces.
  • Properly insulate walls and ceilings.
  • Grade ground so that it drains surface water away from home.

Icon representing a fan Other preventive measures

  • Use easy to clean paint and wallpaper, especially in bathrooms.
  • Install a timer switch on your bathroom fan, and leave the fan on for 15 minutes after showering.
  • When cooking, try to minimize simmering of liquids and foods.
  • Keep furniture away from outside walls where mold might grow.
  • Replacing carpet with wood or vinyl floor tiles will prevent some of the problems with carpeting.

Cleaning up mold

Use the following guidance to clean small areas of mold in the home (less than about ten square feet or a 3 feet by 3 feet patch). Get professional help if the mold growth covers more than 10 square feet. More information is available from EPA's website.

  • Protect yourself

    At a minimum, wear an N-95 mask (available at hardware stores), disposable gloves, and goggles when cleaning up mold. (Tip: facial hair interferes with the N-95’s seal on your face. It’s best to be clean shaven to ensure the respirator’s filter is operating efficiently.)

  • Wash surfaces

    Wash moldy surfaces with a mild detergent solution, such as laundry detergent or dish soap and warm water. Products with an EPA Safer Choice label are the best choice. Go to the Safer Choice website and find a product under either Laundry Products: Laundry Detergent or Dish Soaps. Select a Fragrance Free product, if you prefer. EPA Safer Choice products have been tested for performance and are the safest in their product class.

  • Dispose of materials

    Throw away materials that cannot be cleaned or are too damaged to reuse. Porous materials, like ceiling tiles, likely cannot be cleaned thoroughly and should be discarded.

  • When to use bleach

    The use of bleach is generally not recommended, unless a sewage release has occurred. If you must use bleach, wipe the surface with a solution of 1/4 cup bleach to one gallon of water. Wait 20 minutes and repeat. Wait another 20 minutes. Never mix bleach with ammonia nor other cleaners because fumes from the mixture are harmful.

  • Rinse surfaces

    After cleaning, rinse the surface with clean water.

  • Dry surfaces

    Dry surfaces quickly and thoroughly after cleaning. You can use a fan, air conditioner or dehumidifier.

Resources for tenants

Tenant/renter responsibilities

As a renter, you must control condensation in your home to prevent mold growth. See the section above for guidance. You also must notify your landlord, in writing, of any water leaks or moisture problems as soon as you notice them.

Landlord responsibilities

As a landlord, you're responsible for maintaining the rental unit. You can do this by:

  • Notifying tenants of the health hazards related to mold exposure and how to prevent mold growth.
  • Fixing any water leaks, moisture problems, and any ventilation or heating issues that may lead to moisture problems.

Resources for low-income renters

For free legal help, counseling, and representation for low-income renters:

For housing counseling services, best practices, and FAQs about landlord-tenant laws:

For complaint inspections:

Resources for renters with asthma

  • King County Weatherization Program: Get help with ventilation improvements and other weatherization for your home by applying to this program from King County Housing Authority. Any home can apply but those with respiratory issues such as asthma or COPD are given priority.
  • King County Community Health Worker Program: This program provides free virtual home visits to King County residents with asthma. They also provide educational materials and supplies such as HEPA vacuums and air purifiers.
  • UW Pediatric Environmental Health Specialty Unit: Provides information and guidance for those with reproductive or pediatric environmental health concerns. Consultations are free, and most are over the phone and email. They may recommend a clinic appointment. Financial help is not available for clinic appointments through this group.

Resources for landlord-tenant disputes

The state Residential Landlord-Tenant Act (RCW 59.18) explains the rights and responsibilities of landlords and tenants. When it comes to mold, the act states that “Your local building and code enforcement officials may take action is building problems are not addressed – they won't respond to mold complaints, so it's important to stress the source of the water problem.”
Contact your local building or code enforcement official to report an unaddressed water or maintenance issue. Here are additional resources:

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