Our objective was to examine the prevalence of cannabis in homes with children and temporal trends in storage practices among caregivers. Caregivers of children ages 1–14 in Colorado, identified through a representative population-based telephone survey, participated in a repeated telephone survey from 2014 to 2017. Representing 79 805 households in Colorado with children, 8.6% (95% CI 7.3 to 10.0) of caregivers reported cannabis in the home. From 2014 to 2017, the prevalence of reporting cannabis in the home increased significantly from 6.9% to 11.2% (p=0.02). Among caregivers who reported cannabis in the home, 91.4% reported storage locations inaccessible to children, such as ‘out of reach’. Fewer, 67.0%, caregivers reported storage in a locked container, such as a cabinet, drawer or safe. In a state with recreational cannabis, an increasing number of children live in homes where cannabis is present. Public health practitioners should promote messages to caregivers about safe cannabis storage practices.