Accessory Dwelling Unit (ADU) Permit in Lafayette, Colorado

Lafayette requires an accessory dwelling unit (adu) permit for: New Accessory Dwelling Units are grouped with New Single-Family Dwelling, Two-Family Dwelling, and Multi-Family Townhomes under the Residential Permits category (not Quick Permits or Small Residential Permits); ADU plans must be submitted no larger than 24 x 36 inches; Use the detached-ADU checklist for detached ADUs or ADUs requiring an addition; use the separate attached-ADU checklist for attached ADUs that do not require an addition; Projects in the Old Town Neighborhood Overlay District (which explicitly lists ADUs among covered project types) must additionally meet the Old Town Neighborhood Additional Requirements, Overlay District Regulations, and Dimensional Standards; Accessory Dwelling Units under 750 sq ft do not require separate water taps, water meters, or water rights if the existing tap is adequate for the increased fixture count; otherwise the owner must install a new tap and pay the difference in tap/meter costs. If your project isn't listed, confirm with City of Lafayette Planning & Building Department, Building Division at 303-661-1451 before starting work.

In Lafayette, the published Building Permit Fee (same valuation-based Exhibit A schedule as new construction) is: $30.00 minimum, scaling per valuation tiers. Additional published fees: Plan Check Fee — 65% of the Building Permit Fee; ADU Water/Utility Tap Fee (if a new tap is required) — $9,304 per unit (water tap/meter) if existing tap is inadequate; $2,865 per unit (water reclamation tap); Affordable Housing Fee — $1.00 per square foot of new residential unit, including unfinished basement. These are the jurisdiction's own published figures — see the fee schedule table and source citations on this page.

New ADUs are grouped with new single-family, two-family, and multi-family construction under the City's 8-to-12-week (first comments) review estimate, followed by 1-2 weeks per subsequent review cycle — considerably longer than the City's Quick Permit or Small Residential Permit tracks.

You'll need: Building Permit Application; Accessory Dwelling Unit Checklist (Detached / Addition); Accessory Dwelling Unit Checklist (Attached, No Addition). See the required-documents checklist on this page for details on each.

Lafayette requires 4 inspection(s) for an accessory dwelling unit (adu) permit, in order: Foundation, Rough Frame, Rough Electrical / Plumbing / Mechanical, Final Inspection. Schedule each through City of Lafayette Planning & Building Department, Building Division (303-661-1451).

Apply through City of Lafayette Planning & Building Department, Building Division at 1290 S. Public Road, Lafayette, CO 80026. Phone: 303-661-1451, email: buildingpermits@lafayetteco.gov. Office hours: City Hall public access hours Monday-Friday, 8am-5pm; Building staff available via phone/email during regular business hours. Main city line (303) 665-5588; Building Division direct line (303) 661-1451; Planning staff (303) 661-1270.. Official information: https://www.lafayetteco.gov/92/Planning-Building-Department.

Lafayette, Colorado has adopted: 2021 International Building Code (IBC) — adopted with an effective date of August 1, 2023, per the 2023 Lafayette Colorado Building Code. Source: City of Lafayette Building Code & Design Information page, https://www.lafayetteco.gov/361/Building-Code-Design-Information; 2021 International Residential Code (IRC) — adopted with the same August 1, 2023 effective date; includes a local amendment requiring Class 4 Impact Resistant Shingles (effective March 15, 2021) for reroofing. Source: same page as above; 2021 International Existing Building Code (IEBC); 2021 International Fire Code (IFC); 2021 International Energy Conservation Code (IECC) — includes local commercial low-slope roof reflectance/emittance requirements per IECC Section C402.3, Table C402.3; 2021 International Fuel Gas Code (IFGC); 2021 International Mechanical Code (IMC); 2021 International Plumbing Code (IPC); 2021 International Property Maintenance Code (IPMC); 2021 International Swimming Pool and Spa Code (ISPSC); 2023 National Electrical Code (NEC) — the City's live Solar Permit Application Process document states 'All work shall comply with the 2023 National Electric Code without amendments.' (re-grounded 2026-07-16 on a live primary source after the Solar Photovoltaic Plan Review and Inspections webpage that previously carried this quote was removed from the site). Source (PDF): https://www.lafayetteco.gov/DocumentCenter/View/17165/Lafayette-Solar--Permit-Process; 2023 Lafayette Colorado Building Code — the City's consolidated adoption document incorporating the 2021 I-Code package plus local strengthening amendments and the 2023 NEC; effective August 1, 2023. Source (PDF): https://www.lafayetteco.gov/DocumentCenter/View/36791/2023-Lafayette-Colorado-Building-Code-Final; Colorado Wildfire Resiliency Code — adopted statewide in 2025; applies within State-mapped low- or medium-risk wildfire areas in Lafayette (128 acres total: 44 acres of open space on the southeast edge of the city, 84 acres along the west side near Nyland Way and Brittney Lane). Requires non-combustible building materials for new construction in mapped areas and defines defensible-space/fuel-reduction guidelines within 30 feet of structures. Source: City of Lafayette Building Code & Design Information page, https://www.lafayetteco.gov/361/Building-Code-Design-Information. Local amendments apply — see the Lafayette overview page for the full list.

Not necessarily. ADUs under 750 sq ft do not require a separate water tap, meter, or water rights if the existing tap is adequate for the increased fixture count. If not, the owner must install a new tap and pay the difference in tap/meter costs.