Seattle, WA Landscaping Rules: Native Plants (2026)
Key Facts
- Governing section
- SMC 23.86.019
- Native/drought-tolerant bonus
- 0.1 multiplier
- Rainwater irrigation bonus
- 0.2 multiplier (50%+ harvested rainwater)
- Hardscape cap
- Permeable paving + structural soil ≤ 1/3 of score
- Related FAR incentive
- 0.6 score can raise FAR to 2.0 (SMC 23.44.050)
Summary
Seattle's Green Factor landscaping standard, set out in SMC 23.86.019, awards a 0.1 bonus multiplier to any landscaping that consists entirely of drought-tolerant or native plant species, on top of credit already earned for the planted area itself.
Development standards for certain areas require landscaping that meets a minimum Green Factor score. All required landscaping shall meet standards promulgated by the Director to provide for the long-term health, viability, and coverage of plantings. These standards may include, but are not limited to, the type and size of plants, spacing of plants, depth, and quality of soil, use of drought-tolerant plants, and access to light and air for plants. ... G. Bonuses applied to Green Factor landscape elements: 1. Landscaping that consists entirely of drought-tolerant or native plant species 0.1
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Municipal Code: Supplement 44 Update 1).
Full Breakdown
0 for bioretention facilities or preserved trees at least 6 inches in diameter at breast height. 4 has the applicant divide the resulting Green Factor numerator by lot area to get the final score. a). 1), so a native-plant bed that is also visible from the street and rain-irrigated can stack multiple bonus multipliers. The Director sets the underlying planting standards -- plant type and size, spacing, soil depth and quality, use of drought-tolerant plants, and access to light and air -- under subsection A's opening sentence.
g), which keeps the native/drought-tolerant plant bonus meaningfully tied to actual planting rather than hardscape substitutes. 6, among other options, showing the score set here has real zoning consequences beyond the landscaping plan itself.
Violations & Fines
Green Factor is a development-standard compliance requirement checked at permit review by the Department of Construction and Inspections (SDCI), not a freestanding code-enforcement offense -- a landscape plan that fails to reach the zone's minimum Green Factor score is rejected or conditioned at the permit stage rather than cited after the fact. Once a permit is issued with a Green Factor landscape plan attached, failing to install or maintain the credited landscaping as approved is enforceable the same way as any other unbuilt or altered condition of an approved Master Use Permit, through SDCI's standard code-compliance process.
Frequently Asked Questions
Does planting native species alone satisfy Seattle's Green Factor requirement?
Can a native-plant bed and a rainwater-irrigated bed be the same area for bonus purposes?
Who sets the plant standards behind the Green Factor score?
Sources & Official References
Other rules in Seattle
Compare Seattle to another location·View the Washington landscaping rules overview
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Native Plants in Nearby Cities
How other cities in King County handle native plants.