Given the right environmental conditions, adult mosquitoes can lay their eggs on just about any standing body of water. Some mosquitoes can lay hundreds of eggs in as little as a 1/4 inch of water. The water found throughout stormwater systems provides excellent breeding habitat for mosquitoes. In Cowlitz County, we treat over 3,000 catch basins and monitor 8,000 more every year. These catch basins are treated during the months May and June.

Please watch the following videos and explore the additional resources below to learn more about the interactions between stormwater systems and mosquitoes.

For more information on the interactions between mosquitoes and stormwater structures, please review the United States Environmental Protection Agency (EPA) informational brochure.