They generally don't breed in large bodies of water where the water is flowing. They moatly breed in the little stagnant pools of water that collect in other spots because of poor drainage or things like tires, empty pots, and other trash being left out in the rain. There exist these little pellets that poison those stagnant puddles for the mosquito, but not your pets. That and proper drainage around your house will do wonders to reduce the excess population. Pointing a fan to blow out at any open window can help too, but proper screens (with a fine enough mesh) would help more. Mosquitoes don't like a stiff breeze.