Setbacks & Height Limits in Seattle

This guide explains the basic setback and height rules for residential construction in Seattle, governed by Seattle Municipal Code (SMC) Title 23 — Land Use Code. Exact numbers depend on your specific zone, overlay districts, Environmentally Critical Areas (ECAs), and lot shape, so always confirm with the Seattle Department of Construction & Inspections (SDCI) before finalizing plans.

What Are Setbacks?

A setback is the minimum required distance between a building and a lot line. In Seattle, setbacks are measured from the property line to the nearest point of the structure. Eaves, bay windows, chimneys, and similar features have their own projection rules under SMC 23.44.014.

Seattle specifies front, side, and rear setbacks separately for each zone. Corner lots have two "front" setbacks (one per street frontage) plus one interior side and one rear.

NR Zones (Formerly Single-Family)

Seattle rebranded its Single-Family zones as Neighborhood Residential (NR) to reflect state and local legislation that opened these areas to more housing types — including ADUs and, increasingly, small-scale "middle housing." The old SF 5000, SF 7200, and SF 9600 designations correspond roughly to NR3, NR2, and NR1, distinguished mainly by minimum lot size.

The base setback, height, and lot coverage standards are nearly identical across NR1/NR2/NR3 — the lot-size floor is what primarily changes.

Typical NR Zone Setbacks

Based on SMC 23.44.014 (yards), typical Neighborhood Residential minimum setbacks are:

These are base numbers. Lots with unusual depth, pipe-stem configuration, or ECA overlays may see different requirements. Accessory structures, including DADUs, have their own yard table.

Height Limits

Under SMC 23.44.012, the base maximum building height in NR zones is 30 ft, measured from average grade. A pitched-roof bonus of up to 5 ft is available if the ridge is symmetrical and the pitch meets code. For detached accessory dwelling units (backyard cottages), the height limit is higher than it used to be under recent ADU rule updates — check SDCI Tip 116 for the current figure.

Height rules get more complicated in:

• Hillside and ECA areas — height may be measured from existing grade, with extra massing restrictions
• Lowrise (LR1/LR2/LR3) multifamily zones — 30–40 ft plus roof features
• Commercial and mixed-use zones — set by height maps, often 40–240+ ft
• Shoreline and view corridor overlays — may lower the base height

Lot Coverage and FAR

Two numbers besides setbacks and height shape how big a house can get:

• Lot coverage — In NR zones, maximum building coverage is generally 35% (SMC 23.44.010). Smaller lots under 5,000 sq ft use a formula of 1,000 sq ft plus 15% of lot area.
• Floor Area Ratio (FAR) — Seattle NR zones cap total floor area via a FAR limit (commonly 0.5 base, with small bonuses for certain forms). LR and commercial zones use higher FAR values tied to height.

ADU / Backyard Cottage Rules

Seattle is one of the most ADU-friendly cities in the country. Under Washington HB 1337 (2023) and earlier 2019 Seattle ordinance changes:

• Up to 2 ADUs per lot are allowed in most NR areas (one attached AADU plus one detached DADU, or two attached)
• DADUs enjoy reduced setbacks (5 ft rear) and a height bonus above the base 30 ft
• Owner-occupancy requirements were removed
• Off-street parking minimums for ADUs were eliminated

Because state law preempts some local rules, ADU setback and height numbers can differ from the base NR schedule. See the Seattle ADU Rules page and SDCI Tip 116 for the current standards.

Common Exceptions and Encroachments

SMC 23.44.014 allows certain features to project into required yards:

• Eaves, gutters, and cornices (typically up to 18–24 inches)
• Chimneys (up to 2 ft)
• Uncovered porches, stoops, and steps
• Bay windows (limited projection and width)
• Mechanical equipment such as AC condensers (subject to noise and setback limits)

Fences and retaining walls have separate rules in SMC 23.44.040 and related sections.

How to Look Up Your Specific Requirements

1. Find your zoning district — use the Seattle GIS zoning layer linked from SDCI
2. Read the zone chapter — SMC 23.44 for NR zones, SMC 23.45 for Lowrise multifamily, SMC 23.47A for commercial, etc.
3. Check for overlays — ECAs, shoreline, historic districts, and view corridors can modify base rules
4. Ask SDCI — the Applicant Services Center offers zoning questions at (206) 684-8850

Variances

If your project cannot meet the letter of the code, you may apply for a variance from SDCI. Variances require demonstrating hardship tied to the specific lot, not to the owner's preferences, and follow a discretionary review process. See the Variance Application Guide for the general framework.

Official Sources

See the sources linked in the frontmatter for Seattle Municipal Code Title 23, SMC 23.44, and SDCI. This guide is informational and is not a substitute for direct confirmation from planning staff.

Disclaimer: Zoning rules change frequently. Always verify current setback, height, and lot coverage requirements with SDCI or the Seattle Municipal Code before making design or construction decisions.