Colorado House Bill 19-1170: Undefined Levels of Mold or Dampness Can Make a Leased Residential Premises Uninhabitable

By Steve Heisdorffer

One of the 407 bills the Colorado legislature is considering as of the date of this blog post is House Bill 19-1170, the Residential Tenants Health and Safety Act, which can be found at clicking on the link for the recent bill text.  The bill passed the House on February 26 and is in the Senate for consideration. The bill currently adds two substantive conditions to those conditions that make a residential premises uninhabitable.  One is the lack of functioning appliances that conformed to applicable law when installed and that are maintained in good working order. The second is “mold that is associated with dampness, or there is any other condition causing the premises to be damp, which condition, if not remedied, would materially interfere with the health or safety of the tenant…,”  referred to here as “the mold or dampness provision.”  The bill also amends various procedural provisions of Colorado law to make enforcement by a tenant easier and broadens tenant remedies.  The bill grants jurisdiction to county and small claims courts to grant injunctions for breach.  This article focuses on the mold or dampness provision.

The mold or dampness provision is vague and will likely lead to abuse.  First, there is mold everywhere.  While expert witnesses routinely testify about the level of exposure that is unacceptable, no generally accepted medical standards for an unacceptable level of mold exposure currently exist, and each person reacts to mold differently.  There is no requirement in the bill that mold exposure exceed levels that are generally considered harmful by experts in the field, or even in excess of naturally occurring background levels.  Second, some sources estimate that there are over 100,000 different species of mold.  No harmful effects have been shown for many species of mold, while other species of mold are considered harmful.

It could be argued that the provision that the condition “materially interfere with the health or safety of the tenant…” provides the standard for the level of exposure and the type of mold.  Unfortunately, there are wide disagreements about what level of exposure would “materially interfere” with health or safety, and what may be completely benign to the average person may interfere with the health and safety of a specific individual.

More troubling, our society’s general concerns about mold have helped create a cottage industry of self-proclaimed mold experts willing to make dubious claims under oath.  The medical community in general has been slow to discipline doctors that are willing to testify without any scientific support that cancer, memory loss, autism and other diseases or conditions were caused by mold exposure. The same general concerns about mold have led to the creation of several laboratories that provide mold test results of no known medical value– for the right fee.  In short, in the current climate, the limitation that the alleged mold or dampness materially interferes with the health or safety of the tenant is no limitation at all.

For additional information regarding House Bill 19-1170 or about construction defect litigation in Colorado, generally, you can reach Steve by telephone at (303) 653-0044 or by e-mail at


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