Thornton, CO Animal Ordinances: Dog Leash Laws (2026)

Section 6-7(a) makes it unlawful for an owner to fail to prevent a domesticated animal from running at large in the city; the only affirmative defense is that the animal was contained entirely on private property with the consent of whoever lawfully possesses that property. Running at large is defined in Section 6-1 as an animal not restricted to its owner's premises or not under a person's effective and immediate control, and common areas of townhouse, condo, or apartment developments never count as an owner's premises for this purpose.

' Animal control officers, per Section 6-8, must take any at-large animal into custody and impound it at the animal shelter under Section 6-9, where the owner must pay the impound fee, boarding fee, and any veterinary charges before reclaiming it; unclaimed animals may be sold, adopted out, or destroyed after five days. Officers may enter any property except a dwelling, using reasonably necessary force, to catch a loose animal under Section 6-13, but cannot enter a home's interior without a court order or an adult occupant's consent.