Accessory Dwelling Unit (ADU) Permit in Post Falls, Idaho

Post Falls requires an accessory dwelling unit (adu) permit for: ADU may be detached, attached, or a basement conversion; must have its own electricity, kitchen, and sanitary facilities; Size limited to 50% of the primary residence's living area or 1,000 sq ft, whichever is smaller; Only one ADU allowed per lot; one of the two dwelling units on the lot must be owner-occupied; Detached ADUs must be set back behind the front of the primary residence (corner lots may place the ADU on the street-side yard); One additional paved off-street parking space required; No separate driveway approach permitted unless from a rear-loaded alley, or a side street on a corner lot; Building materials must be consistent with the primary residence; no more than one entrance visible from the street; primary residence entrance must remain clearly visible and street-facing; An existing accessory structure may be converted to an ADU if it is brought up to all currently adopted building code requirements; Detailed site plan required, drawn to scale, showing full property extents, setbacks, and all existing/proposed structures with square footage; ADU must comply with lot coverage, height limitations, and setback requirements for its underlying zoning district; Apply through the Community Development Portal using the standard Residential Building Permit application. If your project isn't listed, confirm with City of Post Falls Community Development Department, Building Division at (208) 773-8708 before starting work.

No. Post Falls has not published a distinct ADU permit fee category — ADU construction is permitted under the standard Residential Building Permit and billed at the applicable per-square-foot valuation rate (new living space, addition, or basement finish) from the City's Fee Schedule.

Post Falls's published plan-review target for an accessory dwelling unit (adu) permit is 10–10 business days.

You'll need: Building Permit Application; Post Falls Accessory Dwelling Units General Information; Site Plan. See the required-documents checklist on this page for details on each.

Post Falls requires 4 inspection(s) for an accessory dwelling unit (adu) permit, in order: Foundation, Framing, Mechanical/Electrical/Plumbing Rough-In, Final. Schedule each through City of Post Falls Community Development Department, Building Division ((208) 773-8708).

Apply through City of Post Falls Community Development Department, Building Division at 1st Floor of City Hall, 408 N Spokane St, Post Falls, ID 83854. Phone: (208) 773-8708, email: permits@postfalls.gov. Office hours: 8:00 a.m. to 5:00 p.m., Monday through Friday. Dedicated Building Inspections line: (208) 457-3334 — leave permit number, job address, inspection type, and desired inspection date; requests left after midnight the night before cannot be scheduled for the following day.. Official information: https://www.postfalls.gov/175/Building.

Post Falls, Idaho has adopted: Idaho has a mandatory statewide building code administered by the Idaho Division of Building Safety (DBS, now organizationally under the Division of Occupational and Professional Licenses / DOPL) under the Idaho Building Code Act, Idaho Code Title 39, Chapter 41, negotiated and adopted through the Idaho Building Code Board. Local jurisdictions that adopt and locally administer the code must enforce it at least as strictly as the state minimum; Post Falls administers its own Building Division for building, electrical, plumbing, and mechanical permitting within city limits. Source: City of Post Falls Current Adopted Codes and Design Criteria (Community Development Department, rev 02/16/25), https://www.postfalls.gov/DocumentCenter/View/750/Current-Codes-and-Design-Criteria-PDF; 2018 IBC (International Building Code), as adopted by the State of Idaho Building Code Board and locally administered by the City of Post Falls. Source: City of Post Falls Current Adopted Codes and Design Criteria (rev 02/16/25); 2018 IRC (International Residential Code), as adopted by the State of Idaho Building Code Board and locally administered by the City of Post Falls. Source: City of Post Falls Current Adopted Codes and Design Criteria (rev 02/16/25); 2018 IEBC (International Existing Building Code). Source: City of Post Falls Current Adopted Codes and Design Criteria (rev 02/16/25); 2018 IECC with 2012 Amendments for Residential (International Energy Conservation Code). Source: City of Post Falls Current Adopted Codes and Design Criteria (rev 02/16/25); 2018 IMC (International Mechanical Code). Source: City of Post Falls Current Adopted Codes and Design Criteria (rev 02/16/25); 2017 ISPC (Idaho State Plumbing Code) — Idaho's own state-amended plumbing code, not the Uniform or International Plumbing Code. Source: City of Post Falls Current Adopted Codes and Design Criteria (rev 02/16/25); 2018 IFGC (International Fuel Gas Code). Source: City of Post Falls Current Adopted Codes and Design Criteria (rev 02/16/25); 2023 NEC (National Electrical Code). Source: City of Post Falls Current Adopted Codes and Design Criteria (rev 02/16/25); ICC A117.1-2009 (Accessibility). Source: City of Post Falls Current Adopted Codes and Design Criteria (rev 02/16/25); 2009 IPMC (International Property Maintenance Code), with amendments. Source: City of Post Falls Current Adopted Codes and Design Criteria (rev 02/16/25); The City of Post Falls Building Division directly issues and inspects electrical and plumbing permits within city limits (the Division's own permit-fee schedule lists dedicated Electrical Permits and Plumbing Permits fee tables administered by the City); this reflects local administration rather than direct-state DOPL/Division of Building Safety issuance for in-city work. Source: City of Post Falls Fee Schedule (Community Development Department, rev 10-1-2025), https://www.postfalls.gov/DocumentCenter/View/815/Fee-Schedule-PDF. Local amendments apply — see the Post Falls overview page for the full list.

An ADU cannot exceed 50% of the primary residence's living area, or 1,000 square feet, whichever is smaller. Source: City of Post Falls Accessory Dwelling Units General Information.