Fleas become immune to many chemicals as each new generation is produced. Most fleas live in your pet's environment, not on the fur. For each one you find, there are dozens more that you can't see. This is because fleas can lay about 60 eggs per day, and the lifespan for each flea is about 90 days. Cocooned fleas can hibernate up to a year without feeding. This is why no matter how you treat your home, you must continue long after the fleas seem to be gone. Often a second generation will hatch and you have the problem all over again. It can be extremely difficult to eradicate every flea in your home, but controlling their numbers is possible.
The first step to killing fleas in your home naturally is to clean. Fleas lay eggs in carpets, curtains, furniture and in cracks and crevices. Vacuuming at least once each week can get rid of a significant amount of eggs and fleas. Replace the bag in your vacuum immediately and take it outside each time you vacuum. Eliminate clutter on the floors of your home. This removes hiding places for fleas. Bedding, most importantly your pet's bedding, should also be washed frequently.
One natural method of trapping fleas is to place a dish of soapy water under a light near your pet's sleeping area. The fleas like the warm light and when they hop into the water to get to it, they drown. This method only traps adult fleas, however, but can significantly reduce your home's flea population. Another option is an electric flea trap. These require no chemicals and are effective in killing adult fleas. Use a sticky flea pad to trap the dead fleas so that you can see how many you are eliminating. The trap should remain plugged in near your pet's sleeping area until no more fleas appear on the sticky trap below it.
Diatomaceous earth is not harmful to humans or pets, but it is lethal for fleas. Diatomaceous earth looks like talcum powder, but contains the skeletal remains of plants called diatoms. The dust has sharp edges that cut into the fleas, killing them. Leave a dusting of diatomaceous earth on pet bedding and the carpet, wherever the fleas are most abundant in your home. Also add a teaspoon under baseboards, stoves, cupboards and near the sink. It should be left in areas that might provide a good place for them to hide and lay eggs. The effectiveness doesn't wear off, but you'll have to reapply after vacuuming. Diatomaceous earth can get into cracks and crevices in areas such as wood floors. Continue applying the powder after the flea population appears to be gone.