Colorado Revised Statutes Title 38. Property Real and Personal § 38-12-701. Notice of rent increase

(2)(a) Notwithstanding any other law, in a residential tenancy in which there is no written agreement between the landlord and tenant, a landlord may increase the rent only upon at least sixty days' written notice to the tenant.

(b) A landlord may not terminate a residential tenancy in which there is no written agreement by serving a tenant with a notice to quit pursuant to section 13-40-107 with the primary purpose of increasing a tenant's rent in a manner inconsistent with this section.