ADU Rental Restrictions: Thornton vs Westminster
How do adu rental restrictions rules compare between Thornton, CO and Westminster, CO?
Thornton, CO
Adams County
Long-term rental of an ADU (30+ day leases) is allowed in Thornton with no city license beyond the ADU permit and no city-imposed cap on rental volume. Short-term rental (under 30 days) of an ADU requires a Thornton STR license under Code Sections 18-54 and 18-174 (Ord. 2020-099) at $180/year, $1M liability insurance, primary-residence operation, and collection of Thornton lodging tax plus the State of Colorado lodger's tax. HB24-1152 preempts ADU-specific rental volume caps as of June 30, 2025.
View full Thornton rules →Westminster, CO
Adams County
No data available yet for Westminster.
Key Facts Comparison
| Fact | Thornton | Westminster |
|---|---|---|
| Long-Term Rental License | Not required | - |
| STR License Fee | $180/year (Code 18-54/18-174) | - |
| STR Insurance | $1,000,000 liability minimum | - |
| Primary Residence Rule | Required for STR (>50% occupancy) | - |
| Colorado State Lodger's Tax | 4.25% | - |
| Ad License Display | STR number on every listing | - |
Highlighted rows indicate differences between cities.
Thornton FAQ
Can I list my Thornton ADU on Airbnb?
Yes, but only if the ADU is at your primary residence and you hold an active Thornton STR license under Code 18-54/18-174. Annual fee is $180, $1M liability insurance, and the license number must appear on every advertisement. You must collect Thornton lodging tax and the Colorado state lodger's tax. If you do not live on the property, only long-term leases of 30+ days are allowed.
Do I need a license for a 6-month ADU lease?
No. Long-term residential rentals of 30 days or more do not require a Thornton license. Colorado state landlord-tenant law governs the lease, including warranty of habitability under C.R.S. 38-12-503 and the 2024 just-cause eviction protections. Thornton does not maintain a long-term rental registry.
Westminster FAQ
No FAQs available.
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