Issaquah, WA Landscaping Rules: Weed Ordinances (2026)

Issaquah does not print a height limit for weeds on a residential lot. What the code prints for built lots is a fire code vegetation rule. IMC 16.06.045 amends International Fire Code Section 304.1.2 so that weeds, grass, vines or other growth capable of being ignited and endangering property must be cut down and removed by the owner or occupant. The duty falls on building lots that are either open or contain an occupied or vacant structure, so an empty lot and a developed lot are covered alike. The test is whether the growth can ignite and endanger property, not a measured height.

A numeric limit appears elsewhere, but only for commercial land. Land Use Code § 18.502.030, Vacant or uninhabited commercial property, states that weeds, grass, and other plants may not exceed 24 inches in height above grade, unless the plant is part of an approved landscape plan under Chapter 18.606 IMC or is for tree preservation under Chapter 18.812 IMC. The same subsection requires those properties to be maintained to remove litter, garbage and yard waste, and control noxious/destructive plants. The stated intent is to reduce visual blight, aid in emergency access and fire safety, guard against rodent and pest harborage, and reduce the impact on the natural environment from noxious weeds.

The City also deleted Section 302.4, Weeds, when IMC 16.04.100 adopted the 2021 International Property Maintenance Code, so the property maintenance code does not carry its own weed section in Issaquah. The Land Use Code definitions section, § 18.102.270, defines a weed as thistles, grasses (such as Bermuda grass) or other plants that are a nuisance, hazard, tend to overgrow or choke out more desirable plants, or cause injury to people, animals or a desired flower, garden plant or lawn cover.