Noxious Weed Laws and Regulations

Why These Laws Exist 

Noxious weeds can spread quickly, crowd out native plants, cause costly damage, and harm humans, livestock, and wildlife. Noxious weed laws exist at the state and county level to help us prevent the spread of such weeds by creating requirements for landowners, allowing counties to fund education and enforcement, and maintaining a list of species considered to be noxious in our state.  

This page explains: 

  • Washington State Law and Rule  

  • Landowner Responsibilities 

  • Scope of the Kitsap County Noxious Weed Control Board 

Washington State Law

RCW 17.10 – NOXIOUS WEEDS – CONTROL BOARDS 

This chapter is the foundation of noxious weed law in Washington State. It was created to limit economic loss and adverse effects to Washington's agricultural, natural, and human resources due to the presence and spread of noxious weeds.  

What it does: 

  •  Creates the State and County Noxious Weed Control Boards 

  •  Requires landowners to control certain weeds on their property 

  •  Authorizes inspection, enforcement, and cost recovery for non-compliance 

WAC 16-750 – STATE NOXIOUS WEED LIST 

The Washington State Noxious Weed Control Board is required to adopt a state-wide noxious weed list every year, highlighting any additions or changes to regional control requirements. This list can be found in WAC 16-750.  

What it does: 

  • Contains the Washington State Noxious Weed List 

  • Describes the schedule of monetary penalties for civil infractions 

  • Establishes additional rules for the state noxious weed control board 

 

Landowner Responsibilities

To effectively control noxious weeds across the state, we need everyone to do their part. State law requires landowners to control or eradicate certain noxious weeds if found on their property. These weeds are informally referred to as “regulated” weeds. See below for more details regarding regulated weeds and landowner requirements. 

Which weeds are required to be controlled? 

The state and county weed lists are organized into three classes based on their distribution and priority throughout the state.  

Class A – Eradication is required, state-wide. Species are limited or unrecorded in state. 

Class B – Control is designated by region. Limited or unrecorded in certain regions. 

Class C – Control is typically not required. Wide distribution in region or state. 

Important Note: The Kitsap County Noxious Weed Control Board may designate additional Class B and C weeds for local control within the county. To see which species are regulated locally, view the latest Kitsap County Noxious Weed List here 

What if regulated weeds are not controlled by landowners? 

Our program is here to support landowners in properly managing their noxious weeds. We are happy to work with willing landowners to discuss control options, develop site management plans, and connect them with resources to assist in their efforts. Enforcement is used as a last resort, but may be necessary to prevent high priority weeds from spreading throughout our county. Please respond to any communications sent by Kitsap County regarding noxious weeds on your property, and we will work with you to tackle your weeds.  

Key state laws regarding landowner responsibilities:  

RCW 17.10.010 – See for definitions of “Owner” and “Noxious Weed” 

RCW 17.10.140 – Owner’s duty to control spread of noxious weeds 

RCW 17.10.145 – State agencies’ duty to control spread of noxious weeds 

RCW 17.10.154 – Owners’ agreements with county noxious weed control boards 

WAC 16-750-003 – See for definitions of “Control” and “Eradicate” 

WAC 16-750-005 – State noxious weed list—Class A noxious weeds 

WAC 16-750-011 – State noxious weed list—Class B noxious weeds 

WAC 16-750-015 – State noxious weed list—Class C noxious weeds 

WAC 16-752-610 – WSDA Noxious Weed Seed and Plant Quarantine List 


Kitsap County Noxious Weed Control Board and Local Code 

While most noxious weed law exists at the state level, monitoring and enforcement of these laws is largely handled by the county noxious weed control boards and their staff. Kitsap County’s Noxious Weed Control Program currently has one full time staff member – the Program Coordinator, to handle all inquiries, inspections, and enforcements. This means we have to focus our time primarily on regulated weed infestations, or those that require landowner control.      

Duties and Limitations of the Kitsap County Noxious Weed Control Board 

What we are required to do: 

  • Hold quarterly board meetings, open to the public 

  • Adopt and publish a county noxious weed list annually 

  • Publish an annual notice about the need for noxious weed control 

  • Employ a program coordinator 

What we are allowed do:   

  • Inspect land for the presence of noxious weeds, including private property 

  • Provide education about noxious weeds and other invasive plant species 

  • Designate additional Class B and C weeds for local control  

  • Issue civil infractions for non-compliance with state weed law 

  • Control noxious weeds at the expense of non-complying landowner 

What we cannot do: 

  • Force landowners to control non-regulated noxious weeds, such as Himalayan blackberry, scotch broom, English ivy, and tansy ragwort.  

Local Noxious Weed Code 

Kitsap County Code (Title 18.20) provides detail on the land classification, assessment, and billing process used to fund the county noxious weed control board and program. County code does not require landowners to control nuisance vegetation outside of very specific circumstances, so in most cases enforcement can only be pursued regulated species – Class As and Class B designates.  

The cities within Kitsap County – Bainbridge Island, Bremerton, Port Orchard, and Poulsbo – may have more strict codes regarding nuisance vegetation. We do not enforce city code, so contact your city code compliance office for violations of city regulations.  

 We are here to support you. Please submit an inquiry if you: 

  Have received a notice from the noxious weed control board, 

  Are unsure about a plant on your property, or 

  Need guidance on safe and effective weed control methods