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Zoning certificate · Planning application

450-square-foot backyard cottage approved with conditions

The city approved a one-story, 450-square-foot detached accessory dwelling unit, about 14 feet tall, with its entrance facing the alley. Conditions include a paved path at least 4 feet wide and following the Historic Preservation Commission's approval.

ApprovedCZC26-00183Filed July 8, 2026North End · 404 W Thatcher St+4 related filings
Site plan for 450-square-foot backyard cottage approved with conditions
Site plan from the application documents.
Pin at the reported location; the shaded outline is the primary parcel (Ada County).

From the filing

The application's description as it appears in City of Boise's record. See the official record

The city approved a zoning certificate for a new 450-square-foot, single-story detached accessory dwelling unit with two bedrooms at 404 W Thatcher St in Boise. The unit would be about 14 feet tall and built in the rear of the property, with its entrance facing the alley. The design was previously approved by the Historic Preservation Commission because the property is in a historic overlay district.

ADU

Project name on file: 404 W THATCHER ST

Timeline

  1. Sept. 8, 2026

    Appeal Period: Completed

  2. Aug. 28, 2026

    Review Complete: Completed

  3. Aug. 28, 2026

    Planning and Zoning: Complete

  4. July 21, 2026

    Planning and Zoning: In Review

  5. July 21, 2026

    Assign Reviewers: Completed

  6. July 9, 2026

    Fee Payment: Payment Received

  7. July 9, 2026

    Prescreen Review: Passed

  8. July 8, 2026

    Prescreen Review: In Progress

  9. July 8, 2026

    Application Submittal: ePlanReview

  10. July 8, 2026

    Application filed

Documents

Site plans

  • Site plan for a 450 SF detached accessory dwelling unit, parking pad, walkway, fencing, and tree protection, with pre-permit and permit revisions listed.

    July 21, 2026 · 1 page · 206 KB · PDS-Maps and Drawings

    Download Site plan with proposed accessory dwelling unit

Plans

  • Exterior elevation drawings for an accessory dwelling unit showing north, east, west and south views, with siding, windows, roofing and grade levels labeled.

    July 21, 2026 · 1 page · 2.3 MB · PDS-Maps and Drawings

    Download Elevations, sheet A3
  • Floor plan drawing for a proposed tiny home ADU, with door and window schedules and plans prepared by a design firm.

    July 21, 2026 · 1 page · 249 KB · PDS-Maps and Drawings

    Download Floor plan, sheet A2

Project narrative

  • Applicant's letter describing a 1-bedroom, 450 sf detached ADU with off-street parking, reduced setbacks, lot coverage, permeable pavers, and approved historic design review.

    July 21, 2026 · 1 page · 40 KB · PDS-Letter of Intent

    Download Detailed letter of explanation for detached ADU

Decisions

Notices

Application

  • Application for a 450 sq ft accessory dwelling unit with one bedroom on a detached single-family residential lot in a historic district, filed by an applicant on behalf of the owner.

    July 8, 2026 · 3 pages · 206 KB · PDS-Application

    Download Zoning certificate application for accessory dwelling unit

Photos

  • Photos of nearby house facades and the alley, plus aerial views of the project site with the proposed ADU drawn in, showing the existing detached garage to be removed.

    July 21, 2026 · 4 pages · 413 KB · PDS-Parties of Record

    Download Site photos and aerial views

Correspondence

  • The Boise Fire Department reports no comments on the zoning certificate review, noting building code requirements will apply and are best addressed at building permit stage.

    Aug. 28, 2026 · 1 page · 151 KB · PDS-Agency Comments

    Download Boise Fire Department comments
  • Boise Parks and Recreation asks for the removed Silver Maple's diameter or two replacement trees, or a payment into the tree mitigation fund, given the historic district.

    Aug. 28, 2026 · 2 pages · 133 KB · PDS-Agency Comments

    Download Parks and Recreation comments on tree removal
  • Public Works says the project must connect to the central sanitary sewer, which is available in the adjacent alley, and sewer capacity fees may apply at building permit issuance.

    Aug. 28, 2026 · 1 page · 65 KB · PDS-Agency Comments

    Download Public Works sewer comments
  • Veolia Water Idaho says the ADU needs its own separate water service line and meter, and requires a site plan submitted for review before service is installed.

    Aug. 28, 2026 · 1 page · 385 KB · PDS-Agency Comments

    Download Veolia Water comments
  • Forwarded arborist email assessing two trees: retain the Scotch Pine with protection measures, and remove the volunteer Silver Maple as a structural liability.

    July 21, 2026 · 4 pages · 28.4 MB · PDS-Other Small Docs

    Download Arborist email on Scotch Pine and Silver Maple
  • Veolia Water Idaho provides available water pressure and flow at a nearby hydrant for fire sprinkler design, to be attached to architectural plan sets.

    July 21, 2026 · 1 page · 113 KB · PDS-Other Small Docs

    Download Water company fire flow letter

Other documents

  • Noticing radius map

    Aug. 26, 2026 · 535 KB · PDS-Maps and Drawings

  • Transmittal sheet

    July 22, 2026 · 136 KB · PDS-Transmittal Agencies

  • ADU checklist

    July 21, 2026 · 864 KB · PDS-Other Small Docs

  • Statement of legal interest

    July 21, 2026 · 209 KB · PDS-Statement of Legal Interest

  • Receipt

    July 9, 2026 · 135 KB · PDS-Receipts

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