Historic Mosquito ControlIn 1957, the Washington State legislature passed Revised Code of Washington (RCW) 17.28 – Mosquito Control Districts. This legislation allows for the creation of Mosquito Control Districts and provides guidance and authorities associated with the operation of a District. The primary reason that a Mosquito Control District is formed is for the welfare of the public.

Benton County Mosquito Control District #1 was formed in 1957, but funding and operations did not begin until 1969/1970. The formation of this District was brought about due to a concern for repeated epidemics of encephalitis like those seen in the 1940s and to a lesser extent, the 1950s.

Benton County is listed as having 22 different mosquito species and Yakima County has 36 different species (provided by WA Dept of Health). The District has physically trapped 16 different species of mosquitoes. Some of these species are vectors (an organism that can transmit pathogens) for diseases, like West Nile virus (WNv), St. Louis Encephalitis (SLE) and Western Equine Encephalitis (WEE).

Originally, Benton County MCD consisted of the city of West Richland and county lands surrounding the areas of Benton City, Kennewick and Richland. The city of Richland was annexed into the District in 1970. The cities of Prosser and Benton City were annexed in 1971. In 1990 areas of the city of Kennewick that were not within the District were annexed. The District expanded even more in 1992 with the annexation of Grandview and Mabton.

We are governed by a Board of Trustees that is comprised of appointed representatives from each of the cities and county commissioner districts within the District. This works out to 7 city representatives and 5 county commissioner representatives; 3 for Benton County and 2 for Yakima County.

Funding is generated by a special assessment that is levied against property within the District.

In Benton County, the following considerations are applied:

  • Parcels within the District are classified as unimproved or improved by the County Assessor,
  • An unimproved parcel has been described by the Benton County Assessor’s Office as raw land that has nothing added to it.  An improved parcel is the land plus anything attached to the land, which includes all attachments, both above and below the ground.  In other words, it is land that has been partially or fully developed for use.
  • Accurately assessing the specific benefit of mosquito abatement operations to individual properties is extremely difficult, highly subjective and prone to uncontrollable variables (e.g., weather or fluctuating river levels), and
  • Improved properties are assumed to be occupied, therefore they receive a greater benefit from mosquito abatement services due to the negative public healthimpacts mosquitoes can have on people and animals.
  • Unimproved parcels are assumed to be unoccupied and unused, therefore the benefit derived from mosquito abatement services for unimproved parcels is less than the benefit of improved parcels.
  • Improved properties larger than 0.25 acres often require resources above and beyond routine operations, such as aerial or truck-mounted spraying to prevent and control mosquito populations.

Therefore, in Benton County for 2018, the assessment will be as follows:  Unimproved properties shall be assessed a flat rate of $5.00 per parcel.  Improved properties shall be charged $40 per acre for the first 0.25 acres of land, and $0.50 per acre for land over 0.25 acres. The remaining assessment amount will be equally divided amongst improved properties subject to the benefit assessment at a rate of approximately $13.91 per parcel.

Example #1; an improved property consisting of 1 parcel and 0.6 acres would be charged, in 2018, approximately $13.91 for the improved parcel + $40 for the first 0.25 acres + $0.175 for the remaining 0.35 acres (0.6 - 0.25 = 0.35); for an approximate total of $54.08 in 2018.

Example #2; an individual owns 5 acres of unimproved property that is represented by 1 parcel.  In 2018, this person will pay $5.00 for this property.

In Yakima County, the assessment is $6.60 per acre plus a $1.50 fee that is charged by the county Assessor and Treasurer to administer the benefit assessment.