Catch Basin Program

Treating a catch basin
Treating a catch basin

Catch basins (or storm drains) are preferred habitats for mosquito larvae, especially for the Culex species. This mosquito can carry West Nile Virus and transmit it in the bird population and possibly to humans as well. Treatment in catch basins is an important part of our larval control program. 

Beginning in late May and continuing throughout the summer, we apply larval control products in area catch basins. We use growth regulator products such as methoprene, and bacterial products such as SpinosadBti, Bsph or combination formulations. Rotational use of these products is important to decrease the likelihood of pesticide resistance.

Catch basins are treated in a priority order:

  1. Prior year WNV activity, if any,
  2. Senior centers & over 55 housing developments,
  3. Recreation areas & schools (for schools it must be part of their outdoor IPM plan),
  4. Neighborhoods/high density areas, and
  5. Industrial areas

Our GIS system allows us to track treatments as well as when basins need a re-application. As you can see from the map below, treated basins are green/black, and basins that need treatment are red/black. 


Beginning in 2018 we brought on additional seasonal staff to supplement the work of our full time staff. In 2020 we treated our one-millionth basin since 2003.