Source Reduction is removing breeding sites or making them inhospitable for mosquitoes. This can be as simple as changing out water in a birdbath every 7 days, or can entail extensive drainage practices to reduce the amount of stagnant water available.
Although some of the control methods outlined here are limited to Mosquito Control Districts, all of us can take steps to reduce the amount of mosquito breeding sites where we live. Keep in mind that one female can lay 250 eggs in one batch and within one week those can turn into 250 adults mosquitoes in your backyard. Proper source reduction benefits us all.