8 county-level rules, plus city-specific rules for 3 cities in Multnomah County, Oregon.
Verified from official government sources
Nuisance vegetation complaints in unincorporated Multnomah County are handled by Multnomah County Vector Control and Code Enforcement (503-988-3464). No specific statewide grass height ordinance exists for unincorporated county areas, but excessive overgrowth and nuisance plants are subject to county nuisance regulations.
In unincorporated Multnomah County, trees on private property generally do not require permits for trimming. Trees overhanging county roads must be maintained for safe clearance. Trees in sensitive areas (floodplain, habitat, steep slopes) may require special approval.
Private property trees in unincorporated Multnomah County generally do not require permits for removal unless in sensitive land areas (floodplain, habitat, steep slopes, riparian corridor). Tree removal in sensitive areas requires county land use review.
Multnomah County enforces noxious weed abatement under ORS 105.550 to 105.570 and Oregon Department of Agriculture OAR 603-052. Portland City Code 29.20 requires property owners to remove tall grass and noxious weeds over 10 inches. Armenian blackberry, English ivy, knotweed, and garlic mustard are priority invasives. The Portland Bureau of Development Services Nuisance Inspection Team handles complaints.
Multnomah County unincorporated areas have no standing outdoor water restrictions under normal conditions. Water service is generally provided through municipal systems (Portland Water Bureau, Gresham). Oregon OWRD monitors drought statewide. Emergency curtailment may restrict outdoor use.
Rainwater harvesting is legal and encouraged in Multnomah County. Oregon does not restrict residential rainwater collection under ORS 537. Portland's Ecoroof and Clean River Rewards programs provide stormwater fee discounts for rainwater capture. Oregon Plumbing Specialty Code (OAR 918-750) governs potable rainwater systems. Simple rain barrels require no permits.
Multnomah County actively encourages native plant landscaping through the East Multnomah Soil and Water Conservation District. Portland Title 11 Trees and the Stormwater Management Manual require native or adapted species for certain applications. Oregon's xeriscape preemption under HB 2571 (2023) prohibits HOA bans on native plant landscapes.
Artificial turf is permitted throughout Multnomah County without building permits for residential installations. HOAs cannot prohibit artificial turf under Oregon ORS 94.776 (HB 2571, 2023). Portland's Stormwater Management Manual treats turf as impervious surface for stormwater calculations over 500 sq ft, which may trigger BES review.
3 cities in Multnomah County have their own landscaping rules rules. Each link goes to that city's dedicated page with code citations.
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