How The District Was Formed
In the 1980’s, mosquitoes plagued residents in east Chino and south Ontario. Residents could not control the mosquitoes by themselves, and complaints to City Halls and the County Health Department gave no resolution.
In 1983, small group of citizens from South Ontario pushed to form a Mosquito Abatement District. The County Board of Supervisors agreed to an advisory ballot, called Measure “Y”.
A short, low-budget volunteer campaign distributed printed material, yard signs, and plastic fly swatters and went house-to-house sharing information about the measure. 
1983-1987 District Boundaries
The Measure passed and 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.
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.
By the spring of 1984, trucks, equipment and materials had been purchased and the original staff had been hired. From these humble beginnings, the District has grown and matured to one of the best Vector Control Districts in the State.