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Here in the soggy Northwest, the problem of household mold is quite common. It’s also mostly preventable.

The vast majority of molds are not toxic to humans, but many can trigger allergy and immune responses in the form of skin rashes, runny noses, eye irritation, coughing or congestion. Those who suffer from allergies, asthma or weak immune systems are particularly prone to the effects of mold exposure.

Owners of rental properties in Washington are required to provide a disclosure form to their tenants with information about molds and their risks, how a tenant can prevent mold, and what to do if mold occurs in a rental property.

The one factor that can be linked to all indoor molds is moisture. This makes the prevention of moisture a top priority for rental owners and tenants.

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Mold typically manifests itself with a “musty” odor. Visual clues include white threadlike growths or clusters of small black specks along walls, typically in rooms where moisture occurs such as bathrooms and unheated basements.

Common places to find mold are areas where water has damaged building materials and furnishings, and along walls where warm moist air condenses on cooler surfaces. This can occur inside cold exterior walls, behind dressers and headboards, and in closets where items are stored against walls.

Rooms with both high water usage and humidity, such as kitchens, bathrooms, laundry rooms and basements, are often havens for mold.

When tenants move into a rental unit, they should note on the property-condition checklist if anything looks like a potential source of moisture intrusion, and request that the rental owner address the issue.

Once tenants have taken possession of the unit, they can be held responsible for any moisture and mold occurrences that are not the result of things out of their control, such as a burst pipe and flooding.

For that reason, it’s important that tenants observe all policies related to moisture and proper ventilation as outlined in their rental agreement.

Taking proper precautions to prevent mold growth can include the proper use of all exhaust fans or windows in bathrooms and kitchens, wiping down excess moisture on window panes, and placing furniture in locations that ensure adequate air circulation behind and around objects — particularly along the insides of exterior walls.

Water-damaged items should also be dried or removed within 24 to 48 hours to ensure mold growth cannot occur on those items.

When mold does occur, tenants should always report the issue in writing to the rental owner to ensure they are aware that there may be a moisture problem that requires their attention.

Washington’s Department of Health offers a wealth of information related to molds, including facts about proper precautions for the cleanup of mold. Some of it is tailored to rental owners and tenants. For more information visit and search using the keyword “mold.”

Sean Martin is the director of external affairs of the Rental Housing Association of Washington, a not-for-profit association of more than 5,000 landlord members statewide. Rental Resource is the organization’s biweekly column. For more information for landlords or tenants, visit

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