In the early 1980’s, mosquito problems in East Chino and South Ontario were horrendous.  There were swarms of mosquitoes around the windows and doors of residential homes.  Individual spraying was ineffective and dozens of mosquitoes were still getting into people’s houses.  Nightly household patrols became ritual.  Complaints to City Halls and the County Health Department were met with “No money, Prop 13.”  

The problem continued in this manner until 1983 when a small group of citizens in South Ontario pushed to form a Mosquito Abatement District.  The County Board of Supervisors agreed to an advisory ballot, called Measure “Y”, which was placed on the November, 1983 ballot.

A short, low-budget volunteer campaign consisted of distributing printed material, yard signs, plastic fly swatters and going house-to-house sharing information. 

The Measure passed.  The approval rate was 59.6%.  This was the first Special District election to be approved after Prop. 13.  On December 5, 1983, the San Bernardino County Board of Supervisors created the West Valley Vector Control District.  The District consisted of the Cities of Chino, South Montclair, South Ontario and areas of unincorporated county land, including Chino Hills and the Dairy Preserve.  Each of the Cities appointed one person to serve on the District Board of Directors and the County appointed two.

The Board of Directors met at the Chino Maintenance Yard under the guidance of the San Bernardino County Health Department.  No money was to be collected until late 1984, so the Board agreed to accept an advance on funds from the County Health Department.  This enabled the Board to form contracts with the Department of Health for management and with the City of Chino for the use of an office and yard facilities. 

By the spring of 1984, trucks, equipment, and materials have been purchased and the original staff had been hired.  

In 2007, the District moved its offices to Ontario to be more centrally located to all its residents.  The new building offered up much more than the Chino office had.

in 2014, the District began renovations on its top floor, creating modern meeting space, updated offices, and state of the art labs to increase their ability to respond to diseases in the area.  The District now has the ability to test for disease in house, reducing alert times to hours instead of weeks.