Accessory Structures in Westminster, CO (2026)
2 verified accessory structures rules for Westminster, Colorado, sourced directly from the municipal code and official government pages.
Verified from official government sources
ADU Rules
Westminster permits one accessory dwelling unit per single-family lot, sized 190 to 1,200 square feet with no more than two bedrooms, approved administratively without a public hearing under Section 11-4-19.
Accessory Dwelling Unit Rules in Westminster
Some RestrictionsWestminster Municipal Code Section 11-4-19
(D)Number Permitted: One accessory dwelling unit is allowed per lot...(H)Size Requirements:(1)The minimum size for an accessory dwelling unit shall be 190 square feet.(2)The maximum size for an accessory dwelling unit shall be 1,200 square feet, or 50 percent of the gross floor area of the principal dwelling unit, whichever is less.(3)No accessory dwelling unit shall have more than two bedrooms...
Shed & Carport Rules
Westminster homeowners can skip a building permit for a detached tool shed, playhouse, gazebo, or pergola only if its floor area stays at or under 120 square feet, under Section 11-9-3(A)(2) of the Municipal Code. A shed of 121 square feet or larger, or any accessory structure with plumbing or electrical service, needs a full permit.
Westminster Accessory Shed Permit Exemption
Some RestrictionsWestminster Municipal Code § 11-9-3(A)(2)(a)
A building permit shall not be required for the following: Building: (a)One-story detached accessory buildings or structures used as tool and storage sheds, playhouses, gazebos, pergolas, and similar uses, provided that the floor area does not exceed 120 square feet.
Looking for Adams County county-wide rules?
County ordinances apply to unincorporated areas and may supplement Westminster city rules.
Accessory Structures in Adams County →