Snohomish County, WA Tree Protection: Parkway Planting (2026)
Key Facts
- Governing section
- SCC 30.25.015(8)
- Where required
- Public and private road frontages in UGAs
- Minimum tree size
- 6 ft high, 1.5-in. caliper at planting
- Setback from property line
- 5 feet minimum
- Maintenance duty
- Property owner, including pruning
- Replacement window
- 3 months for dead/damaged trees
Summary
Unincorporated Snohomish County requires street trees as a frontage improvement on new development under SCC 30.25.015(8). Trees go in along public roads and along private roads and drive aisles in residential projects inside urban growth areas, sized and spaced to the county's Engineering and Drainage Design Standards, with upkeep and liability falling on the property owner.
(8) Street trees are required to be planted as frontage improvements along public roads and along private roads and drive aisles in residential developments within urban growth areas. Street trees are not required around turnarounds at the end of road network elements less than 150 feet in length. (9) Property owners shall be responsible for the maintenance (including pruning) and liability of street trees on their property, or where responsibility has been assumed by the owner through a recorded agreement with the county. (10) Utility work shall minimize impact to street trees, both above ground and to root systems below ground.
Official source re-checked September 8, 2026: no newer edition of the code had been published (publisher’s edition: current through legislation passed August 12, 2026).
Full Breakdown
015(8) makes street trees a required frontage improvement along public roads and along private roads and drive aisles in residential developments located within urban growth areas; the only carve-out is for turnarounds at the end of road network elements shorter than 150 feet, where street trees are not required. 015(5): evergreen and deciduous trees at least six feet high at planting, deciduous stock at least one and one-half inches caliper, trees selected to reach at least 20 feet in height within 10 years, and a minimum five-foot setback from adjoining property lines.
015(6). 015(9) puts maintenance, including pruning, and liability for street trees on the property owner, unless the county has taken over that responsibility through a recorded agreement. 015(10) to minimize impact to street trees, both above ground and to root systems below, when working in the right-of-way. 045 gives property owners three months, up to 180 days if timing conflicts with the planting season, to replace a street tree that dies or is significantly damaged.
Violations & Fines
Occupancy can be withheld under SCC 30.25.043 until a qualified landscape designer certifies the street trees are installed as approved, and the department may require a performance security if planting is delayed. After installation, SCC 30.25.045 requires the property owner to replace any street tree that dies or is significantly damaged within three months, or up to 180 days outside the normal planting season, and the county can require a maintenance security device to guarantee the work.
Frequently Asked Questions
Does Snohomish County require street trees on new development?
Who has to maintain a street tree after it's planted?
How big do street trees have to be when planted?
What happens if a street tree dies?
Sources & Official References
Other rules in Snohomish County
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