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Mosquitoes continue to thrive despite lack of rain.

May contain: plant

Lack of rain does not necessarily mean a lack of mosquitoes. In residential areas, utility vaults and the catch basins that allow rainwater to drain into sewer systems have long been recognized as problematic sources of mosquitoes. Landscape irrigation often flows into these vaults and catch basins because of over-irrigation or incorrect placement of sprinkler head nozzles. Because they are shaded, the standing water in these areas is protected from evaporation, providing an ideal habitat for mosquitoes to develop and fly off. Utility vaults and catch basins are known to produce the common house mosquito which can transmit West Nile virus and St. Louis encephalitis virus.

rain barrel

Water conservation efforts may also contribute to mosquito production in neighborhoods. It is imperative that water storage containers are mosquito-proofed and checked on a regular basis to confirm that there are no leaks or openings where mosquitoes can gain access.

Follow these simple tips to protect yourself from mosquitoes and mosquito-borne illnesses:

  • Do not overwater your lawn.
  • Adjust sprinkler heads towards your lawn and plants.
  • Remove items holding standing water around your yard.
  • Cover rain barrels or other water storage containers tightly with a fine mesh screen (1/16 inch).
  • Place mosquitofish in contained water sources such as ponds, water troughs, neglected pools and ornamental water gardens.
  • Wear an effective insect repellent when mosquitoes are most active during dusk and dawn.
  • Wear long sleeves and long pants when outdoors.

Report mosquito issues to the District at 707-285-2200 or online at

The Marin/Sonoma Mosquito and Vector Control District's programs and services are funded through property taxes and benefit assessments, and are provided to all residents in Marin and Sonoma counties for no additional cost. 


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