Colorado allows adults to possess and use cannabis, yet state law lets property owners restrict smoking on their premises, and many leases do. Whether a tenant broke the lease and what that means for the deposit is a question for the lease and an attorney. The practical question at turnover is simpler: the next household should not walk into a house that smells like the last one.

Cannabis smoke carries resinous compounds and strong-smelling terpenes. In a heavily used room the residue can feel tacky on window glass and light fixtures. The odor often seems to fade during a walkthrough with doors open and then come back sharply once the house is closed and warm. Vaporizers and edibles usually leave far less, though concentrates heated at high temperature can still leave film near the spot where they were used.

How it compares with tobacco residue

Color
Often less yellow staining than heavy tobacco use, so damage is easy to underestimate
Concentration
Frequently concentrated in one bedroom, a basement room or the garage
Soft goods
Curtains, blinds and carpet hold it strongly
HVAC
Spreads through returns just like tobacco residue
Grow activity
If plants were grown indoors, check for moisture damage, mold and altered wiring

Planning the cleanup

  1. Map the strongest rooms

    Walk the house after it has been closed for a few hours. Cannabis use tends to cluster, so note where it peaks. That room may need more than the rest.

  2. Strip soft materials

    Window coverings, abandoned furniture and rugs come out first. Decide on carpet replacement only after checking the pad.

  3. Clean hard surfaces with a degreasing cleaner

    Resin responds better to a cleaner that cuts oily film than to plain water. Work from ceiling down, including light fixtures, ceiling fan blades, outlet covers and window glass.

  4. Handle the air system

    Replace the filter, clean returns and registers, and ask whether ducts warrant cleaning based on what an inspection shows.

  5. Retest before deciding on treatment

    After cleaning and a day of ventilation, close the house and smell again. If odor remains, a whole-unit treatment in the vacant house may be the next step.

  6. Prime the worst rooms

    Use an odor-blocking primer on ceilings and walls in the rooms where use was heaviest, after cleaning and any treatment.

Questions for a provider

Ask these before agreeing to a scope.

  1. Have you treated cannabis residue in a vacant house before, and how did it differ from tobacco?
  2. Which rooms do you think need source cleaning and which may need only treatment?
  3. What will you use for a whole-unit treatment, and how long must the house stay empty afterward?
  4. Does anything in the scope require the painter or flooring installer to wait?
  5. If grow equipment was used, do you also check for moisture damage or mold, or should I call someone else?
  6. How will you describe the condition in writing for my records?

General information for Aurora, not a quote or professional advice. In an emergency, call 911.