Zoning › Washington › King County › Seattle

Seattle, WA Zoning

Euclidean-zoning. 15 districts · 4 overlays · 8 applicable state preemptions.

Overview

Code type
euclidean
Naming convention
mixed

NR1/NR2/NR3 (Neighborhood Residential, lot-size tiered), LR1/LR2/LR3 (Lowrise), MR (Midrise), HR (Highrise), RSL (residential small lot — converting to LR1), NC1/NC2/NC3 (Neighborhood Commercial), SM (Seattle Mixed), downtown-specific codes (DOC1/DOC2/DMC/DMR/DH/DRC — Ch. 23.49). Post-HB-1110 compliance restructured NR zones to allow 4 units by-right citywide, 6 near transit. | naming_convention_raw=alphanumeric-prefix-tier ; sub_flags_raw=[washington, heavy-recent-amendment, middle-housing-upzoned, tier-1-city]

Worth knowing
  • June 30, 2025 is a structural discontinuity in Seattle's zoning. Ord. 127219 (Permanent State Zoning Compliance Legislation) restructured NR1/NR2/NR3 dimensional standards in a single ordinance — the largest single-year zoning code change in Seattle's history. Pre-2025 documents, Tip sheets, and guidance materials are stale. SDCI Tip 220 explicitly marked outdated as of July 2025.
  • 4 units by-right on every residential lot citywide, 6 units within ½ mi of major transit OR with ≥2 affordable units. Among the most permissive urban residential upzones of any major US city per Ord. 127219 implementing HB 1110.
  • FAR scales with density, not against it. Seattle's 2025 NR FAR system REWARDS more units with more floor area: 75% FAR for lowest density, 120% FAR for highest density (<1,600 sf/unit). Unusual among US zoning codes — most codes penalize density with tighter FAR.

+ 8 more in Quirks & notes

Districts

res_mf 5res_sf 4mu 3com 3
CodeNameCategory Min lotHeight CoverageFAR Du/acParking Setbacks F/S/R
NR1Neighborhood Residential 1res_sf9,600 sf[4]32 ft[5]0.5[6]0.75[7]—0[8]15[1] / 5[2] / 15[3]
NR2Neighborhood Residential 2res_sf7,200 sf[12]32 ft[13]0.5[14]0.75[15]—0[16]15[9] / 5[10] / 15[11]
NR3Neighborhood Residential 3res_sf5,000 sf[20]32 ft[21]0.5[22]0.75[23]—0[24]15[17] / 5[18] / 15[19]
RSLResidential Small Lotres_sf2,500 sf[25]25 ft[26]———0[27]— / — / —
LR1Lowrise 1res_mf5,000 sf[28]30 ft[29]0.5[30]1.2[31]—0[32]— / — / —
LR2Lowrise 2res_mf5,000 sf[33]35 ft[34]0.5[35]1.4[36]—0[37]— / — / —
LR3Lowrise 3res_mf5,000 sf[38]40 ft[39]0.5[40]2[41]—0[42]— / — / —
MRMidriseres_mf—75 ft[43]—3.2[44]—0[45]— / — / —
HRHighriseres_mf—240 ft[46]—8[47]—0[48]— / — / —
RCResidential-Commercialmu—————0[49]— / — / —
NC1Neighborhood Commercial 1com—30 ft[50]———0[51]— / — / —
NC2Neighborhood Commercial 2com—40 ft[52]———0[53]— / — / —
NC3Neighborhood Commercial 3com—65 ft[54]———0[55]— / — / —
SMSeattle Mixed (transit corridors)mu—————0[56]— / — / —
DOC1 / DOC2 / DMC / DMR / DH / DRCDowntown zonesmu—————0[57]— / — / —

Confidence: confirmed partial under review not found

Overlays

SMC-23.60A
Shoreline Master Program
SPEC
SMC Ch. 23.60A (Seattle Shoreline Master Program; implements RCW 90.58 Shoreline Management Act)

Properties within the shoreline jurisdiction of Puget Sound, Lake Washington, Lake Union, Ship Canal, Duwamish River, Green Lake, and associated wetlands within 200 ft of the ordinary high water mark (OHWM), plus associated shorelands, floodways, and floodplain wetlands as delineated on the Official Shoreline District Map per SMC 23.60A.152.

shoreline_setback_from_ohwm_ftvaries by environment designation (Urban Residential, Urban Commercial, Urban Industrial, Conservancy, Natural)[58]
shoreline_substantial_development_permit_threshold_usd9,047[59]
public_access_required_commercial_development1[60]
height_limit_shoreline_default_ft35[61]
not_updated_by_hb1110_middle_housing1[62]
SMC-25.09
Environmentally Critical Areas
HS
SMC Ch. 25.09 (Regulations for Environmentally Critical Areas)

Parcels containing or within buffers of: steep slopes (≥40% grade), landslide-prone areas, liquefaction-prone soils, peat settlement zones, wetlands and wetland buffers, riparian corridors, flood-prone areas, fish & wildlife habitat conservation areas, and abandoned landfills, as mapped by SDCI per SMC 25.09.012.

steep_slope_threshold_grade_pct40[63]
riparian_buffer_ft_type_s_waters100[64]
wetland_buffer_ft_category_i200[65]
geotech_report_required1[66]
development_prohibited_in_landslide_hazard_bufferdefault; relief only by geotech + SEPA[67]
not_exempted_by_hb11101[68]
SMC-25.12 / 25.16 / 25.20 / 25.21 / 25.22 / 25.24
Historic Districts & Landmarks
HP
SMC Ch. 25.12 (Landmarks Preservation), Ch. 25.16 (Pike Place Market), Ch. 25.20 (Pioneer Square), Ch. 25.21 (International Special Review), Ch. 25.22 (Ballard Avenue), Ch. 25.24 (Columbia City); Sand Point Naval Station HD (Ch. 25.28); Harvard-Belmont HD (Ch. 25.26); Fort Lawton (Ch. 25.30)

Eight designated historic districts (Pike Place Market, Pioneer Square, International Special Review District, Ballard Avenue, Columbia City, Harvard-Belmont, Sand Point, Fort Lawton) plus individual landmark sites and buildings listed on the Seattle Landmarks Register per SMC 25.12.350.

certificate_of_approval_required_exterior_changes1[69]
review_body_per_districtLandmarks Preservation Board or district-specific review board (Pike Place Historical Commission, Pioneer Square Preservation Board, International Special Review District Board, etc.)[70]
demolition_review_required1[71]
sepa_overlay_maintained_by_2025_legislation1[72]
number_of_designated_districts8[73]
MIO
Major Institution Overlay
SPEC
SMC Ch. 23.69 (Major Institution Overlay District)

Approved master-planned institutional campuses: University of Washington (UW), Seattle University, Seattle Pacific University, Harborview Medical Center, Swedish Medical Center, Virginia Mason Medical Center, Children's Hospital, and other institutions with adopted Major Institution Master Plans per SMC 23.69.005.

master_plan_required1[74]
height_and_use_per_master_planset by approved MIMP; may exceed base zone limits[75]
mio_district_height_designator_ftdesignated on map (e.g., MIO-37, MIO-65, MIO-105, MIO-160, MIO-240)[76]
transportation_management_plan_required1[77]
citizen_advisory_committee_required1[78]

State preemptions

WA-HB1110-RCW36.70A.635applies
Qualifying condition
Seattle is a Tier 1 city under HB 1110 (population >75,000 within a contiguous urban growth area with frequent transit service). King County Metro, Sound Transit Link light rail (1 Line + 2 Line under expansion), and Sound Transit Express provide extensive frequent transit coverage across the city. Every residential lot in Seattle is subject to minimum middle housing allowances; lots within ½ mile of a major transit stop (Link station, frequent bus stop with ≥15-min peak headway) qualify for the 6-unit tier when ≥2 units are affordable. | title=HB 1110 — Middle Housing (2023, effective July 1, 2024 / Seattle compliance June 30, 2025) ; effect_on_city=Requires 4-plex by-right on every residential lot citywide; 6-plex by-right within ½ mile of major transit OR when ≥2 units are affordable. Implemented via Ord. 127219 (Permanent State Zoning Compliance Legislation, effective 2025-06-30) restructuring NR1/NR2/NR3 dimensional standards: 32 ft base height (+5 ft pitched roof, +10 ft tree canopy), 50% lot coverage (60% stacked flats/cottages), density-scaled FAR (75%-120%), 15/10 ft front setbacks, 5 ft avg side setbacks, 15/10/0 ft rear setbacks. Design review for middle housing must be 'clear and objective' per HB 1293. SMP and ECA jurisdictions expressly not affected. ; tier=Tier 1 (>75,000 population in UGA with frequent transit)
WA-HB1337-RCW36.70A.681applies
Qualifying condition
HB 1337 applies statewide to all cities planning under the Growth Management Act. Seattle is a GMA-planning city. All residential zones must permit ≥2 ADUs per lot (any combination of attached/detached/conversion), ≤1,000 sf detached ADU size limits, no owner-occupancy, no off-street parking within ½ mi of transit, no setback more restrictive than primary dwelling, no separate impact fees, and condominium ownership permitted. | title=HB 1337 — Accessory Dwelling Units (2023, effective July 1, 2024 / Seattle compliance June 30, 2025) ; effect_on_city=Seattle now allows up to 2 ADUs per lot (may be 2 DADUs), ≤1,000 sf each, up to 32 ft in NR zones (matching primary structure height), rear-yard ADUs within 5 ft of rear property line (or on property line if alley-abutting), 0 parking required, exempt from street improvement requirements, separately saleable via condo ownership. Implemented via Ord. 127219 and SMC 23.44.041. Preempts any prior Seattle ADU restrictions that conflicted with these minima.
WA-HB1181-RCW36.70A.070applies
Qualifying condition
HB 1181 adds a climate change goal and element to the Growth Management Act; applies to all GMA-planning jurisdictions. Seattle's One Seattle Plan (comprehensive plan update in progress 2024-2026) must include a climate element and a climate-resilient sub-element (greenhouse gas reduction + per-capita VMT reduction + resilience actions). Implementation occurs via the comprehensive plan update, not by direct zoning code preemption. | title=HB 1181 — GMA Climate Change Planning (2023, effective July 2023) ; effect_on_city=Requires One Seattle Plan to incorporate climate element aligning with statewide targets, including VMT reduction strategies (which support citywide parking reductions per SB 5258 and transit-oriented upzones). Does not directly preempt any specific Title 23 provision but structurally constrains plan amendment direction.
WA-SB5258applies
Qualifying condition
SB 5258 preempts local parking mandates for affordable, senior, and disabled housing projects. Paired with HB 1110's parking carve-outs (no parking requirements near major transit) and Seattle's longstanding frequent-transit parking reductions, this effectively eliminates most residential parking minimums citywide. Seattle is served by Link light rail (1 Line downtown through U-District to Lynnwood; 2 Line East Link to Redmond), King County Metro RapidRide (A/B/C/D/E/F/G/H lines — 15-min headway), Sounder Commuter Rail (King Street Station), and Seattle Streetcar (First Hill + South Lake Union). | title=SB 5258 — Parking Minimums for Affordable Housing (2023) ; effect_on_city=0 off-street parking required for affordable, senior, and disabled housing citywide per state law. Combined with Seattle's own frequent-transit exemption (SMC 23.54.015), effectively 0 parking required for the vast majority of multifamily development in Seattle. ADUs citywide are exempt from parking minimums per HB 1337.
WA-E2SHB1220-RCW36.70A.070applies
Qualifying condition
E2SHB 1220 amends the GMA housing element to require cities to plan for and accommodate permanent supportive housing, emergency shelters, and transitional housing in at least one residential zone. Seattle must accommodate these uses and has done so via citywide permissions for shelters in NC, C, and SM zones and permanent supportive housing in residential zones. | title=E2SHB 1220 — Comprehensive Plan Housing Element (2021) ; effect_on_city=Seattle cannot prohibit permanent supportive housing in zones allowing residential and must allow emergency shelters in at least one zone. Implemented via SMC §23.42.054 and related use-table entries.
WA-SB5184applies
Qualifying condition
SB 5184 enables ministerial lot splits in residential zones to create additional housing capacity; intended to work alongside HB 1110 middle housing. Seattle must allow ministerial lot splits on qualifying parcels (subject to state minima for resulting lot sizes). | title=SB 5184 — Lot Splitting (2024) ; effect_on_city=Ministerial lot splits permitted per state standards in NR1/NR2/NR3 zones; stacks with HB 1110 4-plex/6-plex allowances on the resulting lots. Implementation via Seattle subdivision code (SMC Title 23 Subchapter III).
WA-HB1293applies
Qualifying condition
HB 1293 requires that all design review standards applied to middle housing (duplex, triplex, fourplex, fiveplex, sixplex, townhouse, cottage housing, stacked flats) be 'clear and objective' — not discretionary. Seattle has historically had an extensive design review process administered by Design Review Boards (East, West, Central, North, Southeast, Southwest); these cannot apply discretionary standards to middle housing. | title=HB 1293 — Clear and Objective Design Review (2023) ; effect_on_city=Seattle's Design Review program cannot subject middle housing projects to discretionary design standards; administrative design review (objective standards only) may still apply. Significant constraint on Seattle's historical practice.
WA-SMA-RCW90.58applies
Qualifying condition
RCW 90.58 (Shoreline Management Act of 1971) requires all cities with shorelines of the state to adopt a Shoreline Master Program. Seattle has extensive Puget Sound, Lake Washington, Lake Union, Ship Canal, Duwamish River, and Green Lake shorelines — one of the largest municipal SMP jurisdictions in the state. | title=Shoreline Management Act (RCW 90.58) ; effect_on_city=Shoreline Substantial Development Permit (SSDP) required for projects within 200 ft of OHWM exceeding statutory threshold (~$9,047 indexed); separate shoreline setback/height/use standards per SMC 23.60A supersede base zoning within SMP jurisdiction. HB 1110 middle housing expressly does NOT apply within SMP jurisdiction — a material carve-out for waterfront parcels.

Adopted building codes

Statewide; update sched May 2026

IBC
2021
IRC
2021
NEC
2023
IFC
2021
IECC (Residential)
2021
IECC (Commercial)
2021

Click a code label to open its state-by-state adoption atlas.

Quirks & notes

  • June 30, 2025 is a structural discontinuity in Seattle's zoning. Ord. 127219 (Permanent State Zoning Compliance Legislation) restructured NR1/NR2/NR3 dimensional standards in a single ordinance — the largest single-year zoning code change in Seattle's history. Pre-2025 documents, Tip sheets, and guidance materials are stale. SDCI Tip 220 explicitly marked outdated as of July 2025.
  • 4 units by-right on every residential lot citywide, 6 units within ½ mi of major transit OR with ≥2 affordable units. Among the most permissive urban residential upzones of any major US city per Ord. 127219 implementing HB 1110.
  • FAR scales with density, not against it. Seattle's 2025 NR FAR system REWARDS more units with more floor area: 75% FAR for lowest density, 120% FAR for highest density (<1,600 sf/unit). Unusual among US zoning codes — most codes penalize density with tighter FAR.
  • Tree canopy bonus on residential height: base 32 ft; if site preserves or plants 10% canopy coverage, height rises to 42 ft (+5 ft pitched-roof bonus in both cases = 37 ft or 47 ft). Green-building incentive embedded directly in base zoning height.
  • Rear setback 0 ft for 3+ units on alley-abutting lots. Combined with alley access for parking/garages, this maximizes developable area on Seattle's many alley-served lots.
  • RSL (Residential Small Lot) zone converting to LR1 in many areas as part of the 2025 compliance restructuring — a legacy zone being folded into Lowrise to simplify the middle-housing regulatory framework.
  • HB 1293 'clear and objective' requirement eliminates discretionary design review for middle housing — a significant constraint on Seattle's historically extensive seven-Board design review program (East, West, Central, North, Southeast, Southwest boards).
  • SMP (RCW 90.58) jurisdiction is expressly EXCLUDED from HB 1110 middle housing provisions per Ord. 127219. Shoreline parcels remain on pre-2025 NR/LR standards. Material for the ~200 ft strip around Puget Sound, Lake Washington, Lake Union, Ship Canal, and Duwamish.
  • Major Institution Overlays (MIO) on UW, Seattle U, Harborview, Swedish, Virginia Mason, Children's Hospital, etc. override base zoning via adopted Master Plans — height designators (MIO-37 through MIO-240+) set individually on the zoning map. Unique Seattle mechanism for institutional campuses.
  • Downtown zoning (SMC Ch. 23.49) is separate from the main zoning code (Ch. 23.44/45/47A). Six distinct downtown zones (DOC1/DOC2/DMC/DMR/DH/DRC) with incentive-zoning MHA contribution requirements for bonus height/FAR. The downtown chapter is effectively its own zoning code.
  • One Seattle Plan Phase 2 pending (2025-2026): will upzone Neighborhood Centers and transit corridors, further altering applicable zones. Freshness tier should be volatile with ≤6-month re-research cadence.

Formulas

Definitions

height
Grade to highest point of structure; pitched roofs ≥4:12 receive +5 ft bonus (SMC 23.44.012).
lot_coverage
Building footprint / lot area.
far
Gross floor area / lot area. Post-2025 NR FAR scales with density (75% to 120%).
du_ac
Dwelling units per gross acre (rarely used in Seattle — NR zones now use units-per-lot rules instead).
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
nr_far_density_scaling
FAR rises with unit count: 75% (>4,000 sf/unit), 80% (4,000-2,201 sf/unit), 100% (2,200-1,601 sf/unit), 120% (<1,600 sf/unit) per Ord. 127219.
nr_tree_canopy_height_bonus
Base 32 ft + 5 ft pitched-roof bonus = 37 ft; if 10% canopy coverage achieved, 42 ft + 5 ft pitched = 47 ft per Ord. 127219.

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.

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Parking
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District Category Height FAR Coverage Setbacks Parking Density Min lot Overlays

Sources & references

Primary source
Seattle Municipal Code Title 23 — Land Use Code
Through Ord. 127219 (HB 1110/1337 compliance) · retrieved 2026-04-19
Citations
  1. [1] §23.44.014
  2. [2] §23.44.014
  3. [3] §23.44.014
  4. [4] §23.44.010
  5. [5] §23.44.012
  6. [6] §23.44.010
  7. [7] §23.44.011
  8. [8] §23.54.015
  9. [9] §23.44.014
  10. [10] §23.44.014
  11. [11] §23.44.014
  12. [12] §23.44.010
  13. [13] §23.44.012
  14. [14] §23.44.010
  15. [15] §23.44.011
  16. [16] §23.54.015
  17. [17] §23.44.014
  18. [18] §23.44.014
  19. [19] §23.44.014
  20. [20] §23.44.010
  21. [21] §23.44.012
  22. [22] §23.44.010
  23. [23] §23.44.011
  24. [24] §23.54.015
  25. [25] §23.43
  26. [26] §23.43
  27. [27] §23.54.015
  28. [28] §23.45.510
  29. [29] §23.45.514
  30. [30] §23.45.510
  31. [31] §23.45.510
  32. [32] §23.54.015
  33. [33] §23.45.510
  34. [34] §23.45.514
  35. [35] §23.45.510
  36. [36] §23.45.510
  37. [37] §23.54.015
  38. [38] §23.45.510
  39. [39] §23.45.514
  40. [40] §23.45.510
  41. [41] §23.45.510
  42. [42] §23.54.015
  43. [43] §23.45.514
  44. [44] §23.45.510
  45. [45] §23.54.015
  46. [46] §23.45.514
  47. [47] §23.45.510
  48. [48] §23.54.015
  49. [49] §23.54.015
  50. [50] §23.47A.012
  51. [51] §23.54.015
  52. [52] §23.47A.012
  53. [53] §23.54.015
  54. [54] §23.47A.012
  55. [55] §23.54.015
  56. [56] §23.54.015
  57. [57] §23.54.015
  58. [58] §23.60A.166
  59. [59] §23.60A.026
  60. [60] §23.60A.160
  61. [61] §23.60A
  62. [62] Ord. 127219
  63. [63] §25.09.020
  64. [64] §25.09.160
  65. [65] §25.09.160
  66. [66] §25.09.080
  67. [67] §25.09.180
  68. [68] Ord. 127219
  69. [69] §25.12.740
  70. [70] §25.12
  71. [71] §25.12.420
  72. [72] Ord. 127219
  73. [73] §25.12-25.30
  74. [74] §23.69.030
  75. [75] §23.69.030
  76. [76] §23.69.008
  77. [77] §23.69.030
  78. [78] §23.69.032

Research status

Publication gates

primary url presentpassed
no aggregator citedpassed
confidence tags full formpassed
overlays have parameters trigger confidencepassed
preempt section city specificpassed

Data quality

58%completeness58 confirmed38 partial
Documented gaps
  • §23.45 Lowrise dimensional table (LR1/LR2/LR3 exact heights + FAR by MHA tier) not retrieved as a complete table.
  • §23.47A NC1/NC2/NC3 height suffix table not retrieved (NC1-30 / NC1-40 / NC2-40 / NC2-55 / NC3-40 / NC3-65 / NC3-85 variations).
  • §23.48 Seattle Mixed subarea tables (SM-U, SM-SLU, SM-NR, SM-YT etc.) not retrieved.
  • §23.49 Downtown zone table (DOC1/DOC2/DMC/DMR/DH/DRC height + FAR + bonus schedule) not retrieved.
  • §23.69 MIO per-institution height designators not enumerated per institution.
  • §23.60A Shoreline Environment Designation-specific setback table (Urban Residential / Urban Commercial / Urban Industrial / Conservancy / Natural) not retrieved.
  • One Seattle Plan Phase 2 Neighborhood Center boundaries and upzone areas pending (2025-2026).

Known issues

freshness:volatiledata:gaps-present

Verification

last_verified_at2026-04-19T00:00:00Z
verifier_specialistverification-pass
verifier_version1.0
verification_resultpassed
narrative_refnarratives/seattle-wa/se4ttl3-2026-04-19-v2.json

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