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.

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 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

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.   

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 mosquitoes.
  • Charge higher rates for parcels over 1 acre based on total parcel size

How To Calculate Your Assessment

If your parcel is

Acre size Assessment Amount
0-1 acres $4.65
1-5 acres $9.30
5-25 acres $13.95
25-50 acres $18.60
50-100 acres $23.25
100-500 acres $27.90
Over 500 acres $32.55

How to Determine if Your Parcel is Within a Surcharge Area

If any part of your parcel is within one of the following described areas, it will be subject to a surcharge.

California Way

All lots connected to California Way

Kalama River Road

Kalama River Road. Begin at 107 Kalama River Road; continue east to 461 Kalama River Road (Parcel 60893). All lots between these two addresses accessed by Kalama River Road.

Mint Farm

Begin at Olive Way and Ocean Beach Hwy. Olive Way to Memorial Park Drive. Memorial Park Drive West to 38th Ave. South on 38th Ave to Industrial Way.  Industrial Way southwest to Washington Way. Washington Way east to Rail Road tracks crossing Washington Way (just west of 34th Ave). Rail line north to Ocean Beach Hwy. Ocean Beach Hwy. to Olive Way.

South Kelso

Begin on Talley Way at Coweeman River Bridge. West to east bank of Cowlitz River. North along east bank of the Cowlitz River to Allen Street. Follow Allen Street east to I-5. Follow I-5 south to Exit 36. Follow Exit 36 Ramp B to Talley Way at Coweeman River Bridge.

Spirit Lake Hwy

Begin at Si Town Road. All lots connected to Si Town Road. All lots connected by road to Spirit Lake Hwy. from Si Town Road to Gallow Road.

West Ocean Beach

Begin at 38th Ave and Ditch 8 (2098 38th Ave- Parcel 107890100) Follow Ditch 8 north to Mount Solo Road. Mount Solo Road south to Willow Grove Connection Road. Willow Grove Connection Road north to junction of Ocean Beach Hwy. Continue north across Ocean Beach Hwy to Coal Creek Road. Following Coal Creek Road north to Pacific Way. Follow Pacific Way east to 38th Ave. Follow 38th Ave. southwest to 38th Ave. and Ditch 8.

Willow Grove

Willow Grove Road and Columbia Point Road.  All lots connected to Columbia Point Road. South on Willow Grove Road to Taylor Sands Road. All lots connected to Taylor Sands Road. Continue southwest on Willow Grove Road all lots connected to Willow Grove Road from Taylor Sands to 7401 Willow Grove Road (Parcel WL1806011)

If your parcel is located in a surcharge area, multiply your rate based on parcel size by 1.5.

For parcels up to 1 acre:  $6.98

For parcel between 1-5 acres: $13.95

For a parcel between 5-25 acres:  $20.93

For a Parcel between 25-50 acres $27.90

For parcels designated as forest lands:  Calculate your rate as provided above and reduce the result by 90%.

District Annual Reports