Accessory Dwelling Unit (ADU) Permit in Broomfield, Colorado

Broomfield requires an accessory dwelling unit (adu) permit for: Maximum one (1) ADU per property zoned for single-unit residential use; no owner-occupancy requirement; ADU may be internal, attached, or detached (including new-build detached structures, Tiny Homes, and Manufactured Homes per BMC Chapter 17-04); travel trailers, RVs, and shipping/storage containers are prohibited as ADUs; Size limit: up to 500 sq ft by right; larger ADUs are capped at the lesser of 50% of the principal dwelling's footprint (excluding garage/porch/similar areas) or 800 sq ft; ADU design must be consistent with the principal dwelling; where no specific zoning design standard applies, the ADU must be clad in a material similar to the principal structure; ADU must tie into the principal dwelling's existing water and sewer connections — no separate water/sewer tap or license required; other utilities (electric, gas, phone, internet) arranged separately with utility providers; Homes on septic systems must coordinate with the Health Protection Division of Health and Human Services (publichealth@broomfield.org, 720-887-2220) to confirm septic capacity; ADU must meet the zone district's applicable setback requirements, except the ADU's side setback is never greater than the principal dwelling's side setback; No new parking required unless (a) adjacent streets disallow on-street parking AND (b) the property is outside a Parking Reduction Area — if both apply, 3 off-street spaces (2 for the principal unit, 1 for the ADU) must be demonstrated; A Declaration of Use must be recorded, stating the ADU's size/location and referencing ongoing BMC compliance; Building permit required using the Building Department's General Permit Application form; contact the Building Division to confirm supporting documents (an ADU Checklist is required as a supporting document); Applicants should confirm HOA rules before submitting, since HOAs may impose additional restrictions. If your project isn't listed, confirm with City and County of Broomfield Building Division (Community Development Department) at 303-438-6370 before starting work.

In Broomfield, the published Building Permit Fee — valuation-based (same schedule as new construction/addition) is: $23.50 minimum ($1-$500 valuation), scaling per the published fee table; above $18,000 the codified BMC 15-03-100 Table 1-A schedule continues (e.g., $69.25 + $14.00/$1,000 from $2,000-$25,000, down to $4.75/$1,000 above $500,000). These are the jurisdiction's own published figures — see the fee schedule table and source citations on this page.

Broomfield does not publish an ADU-specific line item on its Current Plan Review times list. An ADU is permitted through the Building Division's General Permit Application as a residential building permit, so the governing published timeline — 7 to 8 weeks (49-56 calendar days), the same figure used for New House / Residential Building Permit reviews — applies. These are stated as goals, not guarantees; confirm current timing with buildingpermits@broomfield.org.

You'll need: General Permit Application; ADU Checklist; Declaration of Use. See the required-documents checklist on this page for details on each.

Broomfield requires 2 inspection(s) for an accessory dwelling unit (adu) permit, in order: Foundation/Framing (detached ADU) or Framing (attached/internal), Final. Schedule each through City and County of Broomfield Building Division (Community Development Department) (303-438-6370).

Apply through City and County of Broomfield Building Division (Community Development Department) at George Di Ciero City & County Building, One DesCombes Drive, Broomfield, CO 80020. Phone: 303-438-6370, email: buildingpermits@broomfield.org. Office hours: Monday-Friday, 8:00 a.m. to 5:00 p.m., except holidays; payments accepted 9:00 a.m. to 4:00 p.m. Over-the-counter Plans Analyst consultations available Tuesdays 9am-Noon and Thursdays 1-4pm. Chief Building Official: Tim Pate, tpate@broomfield.org. Permits cannot be submitted through the Online Portal — all permit application documents, revisions, and affidavits must be emailed to buildingpermits@broomfield.org.. Official information: https://www.broomfield.org/174/Building.

Broomfield, Colorado has adopted: Colorado is a home-rule state with NO single statewide building code — each municipality and county adopts and amends its own code edition(s). The only statewide floor requirements are energy-code related (HB22-1362, the Colorado Energy Code Board / Model Low Energy and Carbon Code process) and, for accessory dwelling units, HB24-1152 (statewide ADU standards for eligible jurisdictions). Applicants working in any other Colorado city or county must independently confirm that jurisdiction's own adopted code edition and amendments — do not assume Broomfield's editions apply elsewhere. Source: Colorado Energy Office, Colorado Department of Local Affairs.; City and County of Broomfield Ordinance No. 2295, adopted by Broomfield City Council, effective April 15, 2026: adopts the 2024 International Building Code, 2024 International Residential Code, 2024 International Mechanical Code, 2024 International Plumbing Code, 2024 International Fuel Gas Code, 2024 International Existing Building Code, and 2024 International Fire Code (2024 ICC code series), plus the Colorado Low Energy and Carbon Code (state Model Low Energy Carbon Code / MLECC amendment package). Source: City and County of Broomfield Building Code Information page and Building Division page.; 2023 National Electrical Code (NEC) — City and County of Broomfield began enforcement August 1, 2023, based on the State of Colorado's statewide NEC adoption (Colorado state law requires uniform statewide adoption of the NEC only, per the State Electrical Board). Broomfield will begin enforcement of the 2026 NEC on August 1, 2026, per the State Electrical Board's adoption schedule. Source: City and County of Broomfield Building Code Information page.; Broomfield Municipal Code (BMC) Title 15 (Building and Construction) codifies the locally-amended code editions and permit-fee authority (BMC 15-03-100); BMC Title 17 (Zoning), Chapter 17-32, governs accessory uses including fences (17-32-140) and accessory dwelling units (17-32-160 / 17-04-089). Source: City and County of Broomfield Building Code Information page; Municode library.; Wildland Urban Interface (WUI) Code: a state-mandated model code (Colorado Wildfire Resiliency Code Board) that all Colorado jurisdictions must adopt by March 1, 2026 and enforce by June 1, 2026 (both deadlines confirmed on the City's dedicated 'Broomfield Voice' WUI project page, itself last updated 2026-04-15). The City's Building Division page still carries unchanged 2025-vintage text (re-fetched live 2026-07-23, identical to the 2026-07-18 and 2026-07-03 captures) stating Broomfield had not yet held its adoption hearing and was not expected to consider adoption until early 2026. The dedicated Broomfield Voice WUI page (also re-fetched live 2026-07-23, unchanged since its 2026-04-15 update) is more current and explicit: as of its last update the Wildfire Resilience Code 'has not been adopted by Broomfield,' hearing dates are 'not yet set,' and adoption-ordinance readings 'are not anticipated to occur until the second half of 2026.' Both the March 1, 2026 statewide adoption deadline and the June 1, 2026 enforcement deadline have now passed with no adoption on record on either page — Broomfield's WUI code is not yet in effect as of today. Confirm current status directly with the Building Division before relying on it. Source: City and County of Broomfield Building Division page, 'Wildland Urban Interface Code' notice; City of Broomfield ('Broomfield Voice'), '2025 Colorado Wildfire Resiliency Code' project page and its 'Key Dates' tab.. Local amendments apply — see the Broomfield overview page for the full list.

One ADU per property zoned for single-unit residential use. Any ADU can be up to 500 square feet by right; larger ADUs are capped at the lesser of 50% of the principal dwelling's footprint (excluding garage/porch) or 800 square feet. Source: City and County of Broomfield Accessory Dwelling Units page and ADU FAQ handout (Planning Division, updated 11/4/25).