Overview
- Boise replaced its 30-year-old euclidean code with the Modern Zoning Code effective 2023-12-01 (Ord. 27-23). The 2025-07-01 reorganization (Ord. 25-25 / ZOA25-00003) further amended the code and consolidated tables. The Legacy Zoning Code applies only to applications submitted before 2023-12-01.
- R-1A density is 2.1 du/ac (gross-acre conversion of the 20,000 sf min lot) — explicitly enumerated in Table 11-02.3 rather than left as the implicit lot-size reciprocal. Similar for R-1B (4.8 du/ac) and R-1C (12.4 du/ac).
- R-2 and R-3 list density as N/A — controls intensity through min lot size + envelope + form rather than du/ac cap; allows higher effective densities than the predecessor R-OD / R-3 / R-4 districts under the Legacy Code.
+ 9 more in Quirks & notes
Districts
| Code | Name | Category | Min lot | Height | Coverage | FAR | Du/ac | Parking | Setbacks F/S/R |
|---|---|---|---|---|---|---|---|---|---|
| R-1A | Residential Large Lot | res_sf | 20,000 sf[4] | 35 ft[5] | — | — | 2.1[6] | — | 15[1] / 10[2] / 20[3] |
| R-1B | Residential Suburban | res_sf | 9,000 sf[10] | 35 ft[11] | — | — | 4.8[12] | — | 15[7] / 10[8] / 20[9] |
| R-1C | Residential Traditional | res_sf | 3,500 sf[16] | 40 ft[17] | — | — | 12.4[18] | — | 15[13] / 5[14] / 15[15] |
| R-2 | Residential Compact | res_mf | 2,500 sf[22] | 45 ft[23] | — | — | — | — | 10[19] / 5[20] / 15[21] |
| R-3 | Residential Urban | res_mf | 1,500 sf[27] | 50 ft[28] | — | — | — | — | 10[24] / 5[25] / 15[26] |
| MX-1 | Mixed-Use Neighborhood | mu | — | 45 ft[32] | — | — | — | — | 0[29] / 0[30] / 10[31] |
| MX-2 | Mixed-Use General | mu | — | 45 ft[36] | — | — | — | — | 0[33] / 0[34] / 10[35] |
| MX-3 | Mixed-Use Active | mu | — | 70 ft[40] | — | — | — | — | 0[37] / 0[38] / 10[39] |
| MX-4 | Mixed-Use TOD Node | mu | — | 70 ft[44] | — | — | — | — | 0[41] / 0[42] / 10[43] |
| MX-5 | Mixed-Use Downtown | mu | — | — | — | — | — | — | 0[45] / 0[46] / 0[47] |
| I-1 | Industrial Light | ind | — | 55 ft[51] | — | — | — | — | 20[48] / 0[49] / 0[50] |
| I-2 | Industrial Heavy | ind | — | 55 ft[55] | — | — | — | — | 20[52] / 0[53] / 0[54] |
Confidence: confirmed partial under review not found
Overlays
Parcels within Boise Airport (KBOI / Gowen Field) AICUZ APZ-I, APZ-II, Clear Zone, and FAR Part 77 imaginary surfaces. Primarily south and southwestern Boise. Boise Airport is joint-use with the Idaho Air National Guard 124th Fighter Wing (Gowen Field), so AICUZ applies in addition to FAR Part 77.
| far_part_77_height_restrictions | True |
|---|---|
| aicuz_apz_use_compatibility_restrictions | True |
| aicuz_clear_zone_use_restrictions | no residential, public assembly, hazardous-materials uses in Clear Zone |
| avigation_easement_disclosure_required | True |
| noise_disclosure_required_in_dnl_65plus_zone | True |
Boise Front foothills parcels above the Boise River terrace; slopes ≥15% (typical hillside-overlay threshold) along Hill Road, Bogus Basin Road, Warm Springs Mesa, and the foothills above the State Capitol.
| slope_threshold_for_overlay_pct | 15 |
|---|---|
| additional_grading_drainage_review_required | True |
| cut_fill_limits | True |
| slope_density_reduction_factor | True |
| geotechnical_report_required_for_significant_slope | True |
Foothills WUI area along the Boise Front; ignition-prone vegetation interface; supplements the International Wildland-Urban Interface Code as locally adopted.
| ignition_resistant_construction_required | True |
|---|---|
| defensible_space_required_ft | 30 |
| roof_class_a_required | True |
| vegetation_management_required | True |
| iwuic_referenced_construction_standards | True |
FEMA-mapped Special Flood Hazard Areas (Zone A, AE) along the Boise River, Cottonwood Creek, Crane Creek, and Warm Springs Mesa drainages.
| fema_nfip_standards_adopted | True |
|---|---|
| bfe_plus_freeboard_required | True |
| freeboard_ft | 1 |
| no_rise_certification_required_in_floodway | True |
| elevation_certificate_required | True |
Boise River corridor and the city's adopted Boise River System boundary (riparian setback and greenbelt protection).
| riparian_setback_required | True |
|---|---|
| greenbelt_dedication_required_along_corridor | True |
| habitat_restoration_standards | True |
| limit_on_impervious_in_corridor | True |
Locally-designated historic districts (e.g., Warm Springs Avenue, Capitol Boulevard, Old Boise) and individually-designated landmarks; Historic Preservation Commission jurisdiction.
| certificate_of_appropriateness_required | True |
|---|---|
| design_review_by_historic_preservation_commission | True |
| demolition_review_required | True |
| secretary_of_interior_standards_for_rehab_referenced | True |
Capitol Boulevard corridor from the Idaho State Capitol south to the Boise Depot — the city's principal ceremonial corridor.
| capitol_boulevard_view_corridor_preserved | True |
|---|---|
| build_to_line_required | True |
| ground_floor_active_use_required | True |
| design_review_required | True |
Hyde Park neighborhood (13th Street north of the State Capitol grounds); historic streetcar-era commercial node within the North End.
| design_review_required | True |
|---|---|
| scale_and_character_compatibility_required | True |
| façade_transparency_requirement | True |
Near North End neighborhood; supplements the Boise North End National Register listing with form-and-character controls.
| design_review_required | True |
|---|---|
| compatibility_with_historic_pattern_required | True |
| limits_on_demolition_for_contributing_resources | True |
Big Sky neighborhood; character overlay supplementing base district form. Specific boundary and parameter details not fully retrieved this pass.
| design_review_required | True |
|---|---|
| scale_compatibility_required | True |
Sycamore neighborhood; character overlay supplementing base district form. Specific boundary and parameter details not fully retrieved this pass.
| design_review_required | True |
|---|---|
| scale_compatibility_required | True |
State preemptions
Non-applicable laws (1)
Adopted building codes
Statewide; extensive NEC amendments
Click a code label to open its state-by-state adoption atlas.
Quirks & notes
- Boise replaced its 30-year-old euclidean code with the Modern Zoning Code effective 2023-12-01 (Ord. 27-23). The 2025-07-01 reorganization (Ord. 25-25 / ZOA25-00003) further amended the code and consolidated tables. The Legacy Zoning Code applies only to applications submitted before 2023-12-01.
- R-1A density is 2.1 du/ac (gross-acre conversion of the 20,000 sf min lot) — explicitly enumerated in Table 11-02.3 rather than left as the implicit lot-size reciprocal. Similar for R-1B (4.8 du/ac) and R-1C (12.4 du/ac).
- R-2 and R-3 list density as N/A — controls intensity through min lot size + envelope + form rather than du/ac cap; allows higher effective densities than the predecessor R-OD / R-3 / R-4 districts under the Legacy Code.
- Mixed-use districts MX-1 through MX-5 use a build-to range (Min 0 ft / Max 20 ft) rather than a fixed setback — form-influenced euclidean rather than pure form-based. MX-5 (Downtown) has no codified height cap, deferring to FAR Part 77 imaginary surfaces via AI-O for the southern parts of downtown within KBOI approach geometry.
- Industrial side and rear setbacks are 0 ft (with footnoted exceptions) — narrow industrial parcels can be built lot-line to lot-line. Front setback is 20 ft to preserve street character.
- Idaho's March 2026 housing-reform package (SB 1352, SB 1354, HB 583, HB 800, HB 706, HB 707, HB 585) — all signed by Governor Little — substantially preempts low-density single-family standards in Boise effective 2026-07-01. SB 1352 (starter-home subdivisions) and SB 1354 (ADU by-right) are the most operative: SB 1352 caps R-1A/R-1B/R-1C min lot at 1,500 sf for qualifying starter-home projects; SB 1354 makes ADUs by-right in R-1A and R-1B (already broadly permitted in R-1C/R-2/R-3).
- Boise's housing-incentive program is structured as voluntary density bonus / fee waiver, consistent with Mountain Central v. McCall (Idaho Sup. Ct. 2021) — mandatory inclusionary zoning is ultra vires in Idaho.
- Boise Airport (KBOI) is joint-use with the Idaho Air National Guard's 124th Fighter Wing at Gowen Field — AICUZ applies in addition to FAR Part 77 imaginary surfaces, restricting residential and assembly uses in APZ-I and Clear Zone in south and southwestern Boise.
- Wildland-Urban Interface (WUI-O) exposure on the Boise Front foothills — supplements the locally-adopted International Wildland-Urban Interface Code with defensible-space and ignition-resistant construction requirements layered on Hillside Development Overlay (HS-O).
- Character overlays (HC-O Hyde Park, NC-O Near North End, BC-O Big Sky, SC-O Sycamore) are a notable Boise innovation — they codify form-and-design control in non-historic-listed neighborhoods, supplementing the traditional Historic Design Overlay (HD-O) for designated historic districts.
- Boise's prior v1 record carried v1-converter artifact dimensional values (5,000 sf min lot / 35 ft height / 0.5 lot coverage / 0.5 FAR / 25 ft front / 25 ft side / 10 ft rear) repeated across all five residential districts — this was template bleed, not primary-source data. This v2 ship replaces those with primary-source Title 11 Table 11-02.X values; lot_coverage / FAR / parking are intentionally NULL where Title 11 does not codify them (Boise's residential districts control intensity through envelope + density rather than coverage/FAR caps).
- Comprehensive plan: Blueprint Boise adopted 2019-12-17. LLUPA §67-6508 requires the zoning ordinance to be consistent with the comp plan; Title 11 was crafted to implement Blueprint Boise's housing-supply policies (middle housing in R-1C/R-2/R-3 by-right, mixed-use intensification on transit-anticipated corridors via MX-3/MX-4).
Formulas
Definitions
- height
- Grade to highest point of structure (Title 11 definitions).
- lot_coverage
- Building footprint / lot area.
- far
- Gross floor area / lot area.
- du_ac
- Dwelling units per gross acre.
- setback_front
- Front property line to nearest building face.
- setback_side
- Side property line to nearest building face.
- setback_rear
- Rear property line to nearest building face.
- parking
- Spaces per dwelling unit unless noted.
Capacity calculations
- max_footprint_sf
lot_area_sf * lot_coverage- max_gfa_sf
lot_area_sf * far- buildable_width_ft
lot_width_ft - setback_side_ft * 2- buildable_depth_ft
lot_depth_ft - setback_front_ft - setback_rear_ft- max_stories_approx
max_height_ft / 10
Massing explorer
Interactive 3D comparison across every district. Drag to orbit, scroll to zoom, use the slider to walk districts, and toggle applicable overlays in the right-side panel.
| District | Category | Height | FAR | Coverage | Setbacks | Parking | Density | Min lot | Overlays |
|---|
Sources & references
- [1] §Table-11-02.3
- [2] §Table-11-02.3
- [3] §Table-11-02.3
- [4] §Table-11-02.3
- [5] §Table-11-02.3
- [6] §Table-11-02.3
- [7] §Table-11-02.5
- [8] §Table-11-02.5
- [9] §Table-11-02.5
- [10] §Table-11-02.5
- [11] §Table-11-02.5
- [12] §Table-11-02.5
- [13] §Table-11-02.7
- [14] §Table-11-02.7
- [15] §Table-11-02.7
- [16] §Table-11-02.7
- [17] §Table-11-02.7
- [18] §Table-11-02.7
- [19] §Table-11-02.9
- [20] §Table-11-02.9
- [21] §Table-11-02.9
- [22] §Table-11-02.9
- [23] §Table-11-02.9
- [24] §Table-11-02.11
- [25] §Table-11-02.11
- [26] §Table-11-02.11
- [27] §Table-11-02.11
- [28] §Table-11-02.11
- [29] §Table-11-02.13
- [30] §Table-11-02.13
- [31] §Table-11-02.13
- [32] §Table-11-02.13
- [33] §Table-11-02.15
- [34] §Table-11-02.15
- [35] §Table-11-02.15
- [36] §Table-11-02.15
- [37] §Table-11-02.17
- [38] §Table-11-02.17
- [39] §Table-11-02.17
- [40] §Table-11-02.17
- [41] §Table-11-02.19
- [42] §Table-11-02.19
- [43] §Table-11-02.19
- [44] §Table-11-02.19
- [45] §Table-11-02.21
- [46] §Table-11-02.21
- [47] §Table-11-02.21
- [48] §Table-11-02.27
- [49] §Table-11-02.27
- [50] §Table-11-02.27
- [51] §Table-11-02.27
- [52] §Table-11-02.29
- [53] §Table-11-02.29
- [54] §Table-11-02.29
- [55] §Table-11-02.29
Research status
Publication gates
| primary url present | passed | source.primary_url = https://www.cityofboise.org/departments/planning-and-development-services/planning/zoning/zoning-code/ (official City of Boise PDS zoning code landing page); not an aggregator |
|---|---|---|
| no aggregator cited | passed | scan clean — all citations point to Title 11 section/table refs, Idaho Code section refs, federal CFR refs, or cityofboise.org URLs; no third-party aggregator domains cited |
| confidence tags full form | passed | 57/57 confirmed numeric fields carry c§Table-11-02.X-form citations; 2 partial overlays (BC-O, SC-O) and 1 under_review preemption (HB 706 opt-in) carry paired retrieval_failure_reason |
| overlays have parameters trigger confidence | passed | all 11 overlays have non-empty parameters object (≥3 keys each), explicit geographic_trigger string, status, and citation; 9 confirmed (AI-O, HS-O, WUI-O, FP-O, BR-O, HD-O, CD-O, HC-O, NC-O) + 2 partial (BC-O, SC-O) with retrieval_failure_reason |
| preempt section city specific | passed | 10 Idaho preemption laws evaluated with Boise-specific qualifying_condition_checked (population 250,060; Blueprint Boise 2019; Area of City Impact defined; housing-incentive program structure); not link-stubs |
Data quality
- MX-U, MX-H, I-3, A-1, A-2 dimensional tables not retrieved this pass — captured in not_captured_districts[]
- BC-O and SC-O overlay parameters partial — per-overlay summary pages limited
- HB 706 single-stair opt-in status under_review until post-2026-07-01 ordinance index check
Known issues
Verification
| version | 1.0 |
|---|---|
| claims_checked | 58 |
| claims_verified | 56 |
| verification_failures | BC-O and SC-O overlay parameters carry partial status with explicit retrieval_failure_reason — per-overlay summary pages are not as comprehensive as per-base-district pages on cityofboise.org; HB 706 single-stair adoption status is under_review — effective date is 2026-07-01 (after retrieval), opt-in not yet possible |
| notes | All confirmed claims carry c§Table-11-02.X form citations to per-district summary pages on cityofboise.org which inline the Title 11 dimensional table. Partial claims (BC-O, SC-O, HB 706 opt-in status) carry explicit retrieval_failure_reason. amlegal-hosted full code is Cloudflare-gated; per-district summary pages were the operative primary source. No aggregator domains cited. |
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