About The District

The Cowlitz County Mosquito Control District was established in 1991 under the authority of RCW 17.28 and encompasses all of Cowlitz County.

The district works from March through October to control mosquitoes in Cowlitz County.  The Control District identifies areas with mosquitoes by surveying wetlands, ditches and any standing water for mosquito larvae and trapping adult mosquitoes.  

Areas with mosquito larvae are treated with larvicides by licensed technicians to reduce the mosquito population.  Areas with heavy adult mosquito population are treated with a ultra low volume fogger to reduce the mosquito population.   

Any resident of Cowlitz County may contact the Mosquito Control District to request help with mosquito problems. There is no charge for this service, we are funded by an assessment on all property within the County.

The Mosquito Control District sets adult traps any place in the county where there is a known mosquito problem.  We do this to find concentrations of adults and to test for the presence of Arboviruses such as West Nile Virus.  The Control District also trap for adults on private property if a resident reports a problem.  We set traps at hundreds of locations and cover the entire county.

How We Charge

We only assess owners of land and strive to structure our assessments so that the charge reflects the benefit received. To accomplish this, we do the following:

  • Assess all recorded lots within the District under 1 acre at a flat fee.
  • Add a surcharge to the flat fee to certain areas with known high concentration of mosquitos.
  • Charge higher rates for parcels over 1 acre based on total parcel size