Anchorage ADU permit requirements
Last reviewed: June 22, 2026
Quick answer
Permitting an accessory dwelling unit (ADU) in Anchorage, Alaska means pulling a building permit from the local authority that issues it. ArchPermit tracks 13 source-cited requirements (5 required, the rest conditional) for this jurisdiction. Submittals go through Development Services (4700 Elmore Rd) + ePlans (ProjectDox). These requirements were last reviewed June 22, 2026; confirm the exact forms and fees with the local permitting authority.
A source-cited checklist of what an ADU (accessory dwelling unit) permit package needs in Anchorage. Every item links to its authoritative source; items that vary are flagged to confirm locally.
ADUs are a permitted (by-right) accessory use — the Title 21 use table marks ADU 'P', not conditional; 'the permit shall constitute an ADU permit' (AMC 21.05.070.D.1.b.ii). In the Anchorage Bowl, ADUs are allowed in all residential/commercial zones wherever there's another dwelling, but in R-1/R-1A the ADU must be ATTACHED. One ADU per lot. Owner-occupancy is NOT required — the Feb 2023 reforms eliminated the mandate (Policy AG.37, 2024); an obsolete owner-occupancy affidavit form still exists on muni.org. Size (Bowl): 40% of the primary structure or 900 sf, whichever is larger, up to 1,200 sf. An ADU is built to two-family-dwelling code standards unless it communicates freely with the adjacent unit. Chugiak–Eagle River and Girdwood have their own rules.
- Building/Land Use Permit Application (Residential Permit Worksheet)required
The Residential Permit Worksheet (the permit application) with the ADU checkbox and the 'does the ADU freely communicate with the primary residence?' question.
source · reviewed 2026-06-22 - Final As-Built Survey (pre-CO)required
An AK-registered surveyor's original-stamp as-built, required before any Certificate of Occupancy (copies not accepted).
source · reviewed 2026-06-22 - One (1) Set of Structural Calculationsrequired
Calculations matching the drawings, signed by whoever performed them.
source · reviewed 2026-06-22 - Two (2) Plot Plans, Sealed by an AK-Registered Land Surveyorrequired
Lot ID, lot-line dimensions, easements, drainage, building footprint to 0.1 ft, finished-floor/corner elevations, and driveway location/surface (surveyor sets all lot corners).
source · reviewed 2026-06-22 - Two (2) Sets of Complete Construction Plansrequired
Cross-sections, elevations, floor/roof framing plans, connection details, and structural info meeting wind/seismic loads.
source · reviewed 2026-06-22 - Energy / Heat-Loss Conservation Calculationsconditional
One set, required only if minimum insulation requirements aren't met (ASHRAE 90A-1980).
source · reviewed 2026-06-22 - Flood Hazard Permit + Elevation Certificateconditional
If in/within 300 ft of a flood zone: flood-zone review; if in the mapped floodplain, a Flood Hazard Permit + Elevation Certificate + stamped building-site survey.
source · reviewed 2026-06-22 - Hold Harmless Agreement (Pre-Approved ADU track)conditional
Required only on the optional Pre-Approved ADU catalog track (use of MOA-provided plans), not standard custom ADUs.
source · reviewed 2026-06-22 - On-Site Well &/or Septic Permit or Capacity Determinationconditional
If not on public water/sewer: an upgrade permit or written determination that the existing system has capacity for the added bedroom load.
source · reviewed 2026-06-22 - Owner/Builder Acknowledgement (Form AG.07)conditional
Required only if applying as an owner/builder.
source · reviewed 2026-06-22 - Right-of-Way Permitconditional
Required if the ADU adds a new driveway or utilities extension, or for footing drains to the municipal storm drain.
source · reviewed 2026-06-22 - Soils / Geotechnical Reportconditional
Required if mandated by plat note, in Seismic Hazard Zone 4/5, or where the ADU is on/adjacent to slopes steeper than 1:3.
source · reviewed 2026-06-22 - Stormwater Handout AG.21 (signed)conditional
One signed AG.21 Stormwater Treatment Plan Review (Type 1 SWPPP + Threat Assessment); not required for jobs <500 sf or on piles.
source · reviewed 2026-06-22