If you want to get rid of fleas for good, you will have to do more than just treat your pet. Fleas live and breed in the areas your dog frequents. If your pet spends most of its time in your yard, this is where 90 percent of the flea population lives, breeds and waits for their meal to come trotting by. But before you spray, keep in mind that fleas detest direct sunlight. By clearing any yard debris and unnecessary yard structures and cutting your grass low, you can limit the amount of pesticide needed to treat your yard.
Identify flea hot spots in your yard. Fleas congregate anywhere they are likely to encounter your pet. This includes any outdoor housing, favorite napping spots, feeding areas, and any place your dog rests, sleeps or runs. An effective way to spot hot spots is to walk around your yard wearing white knee-high socks. As the fleas jump around the hot spots, you'll be able to see them against your socks.
Water the ground all over your yard with 1 to 2 inches of water. This will bring any flea larvae present up to the surface of the soil.
Spray flea hot spots with an insecticide labeled for outdoor use on fleas. The entomologists at the University of Kentucky recommend chlorpyrifos (Dursban) and permethrin for atypical infestations. They recommend pesticides that contain IGR (methoprene or pyriproxyfen) for long-term treatment in repeatedly infested areas. Follow the manufacturer's instructions for application rates and methods. Open areas that are exposed to direct sunlight do not need to be sprayed.
Re-treat your yard as necessary at the intervals dictated by your insecticide's manufacturer.