Yes, as basic as this seems, according to an Ohio State article* simple vacuuming can kill up to 96% of the fleas living there. Considering that the toxic topical chemicals claim a 99% kill rate, this is pretty good. And at least vacuuming doesn't leave toxins in your pets' tissues. One additional step is to add some Diatomaceous Earth to the vacuum canister or bag. That will kill any that survive the brushes and whirlwind. Don't forget the pets' bedding and furniture. Quick note on the cited article, it was from 2007 and since then we've seen some issues with the topical that the older article was unaware of when it stated that the topicals were devastating the flea population. In fact the topicals have led to a super flea that is not succumbing to the topicals. But that shouldn't surprise anyone, when the topical packages state that they kill 99% that leaves 1% to carry on and it seems that their offspring are immune.
2) Diatomaceous Earth
3) Combing pets
4) Garlic and Yeast Powders for Pets
I have added garlic and yeast powders that were made for pets to my pets' food in the past. It seems to work, and there is the added benefit that these things are good for our pet in other ways too. It's primarily the garlic that repels the fleas. I found a pure garlic powder for horses at PetsMart once and sprinkled it on the food. Since I also do all the other things listed here, it's impossible to say how much this contributed.
For dogs and ferrets, a good bath is a good start. I would vacuum, DE and comb first. Then the bath will get the few remaining fleas and once gone, the carpets won't re-infest. Just remember when you bath the pet it is not the toxic chemicals that you need so much as the solid 5-10 minutes with the soap soak! Once the pet is wet, apply the shampoo and lather like crazy, touching on all the favorite flea points, the base of the tail, the ears, the under arms (legs), under the chin, etc. The hard part is keeping the pet still for at least 5 minutes and the more the better. It's the time that kills the fleas. When they get wet they "lock down" onto the pet. It takes that much time before they release some and can be washed off. Then make sure the pet is rinsed very thoroughly since any shampoo is drying on a pet. Dry time is always the pet's favorite and just like with the combing, it's a great bonding time. Use a large absorbent towel and have fun! I've heard that those large shamwows really do a good job.
I personally don't believe in bathing cats unless they have a skin condition that requires it and then only under the care of a Vet.
So there you have it. Flea eradication without chemicals. I highly recommend reading the EPA's tips as well as their report on the toxicity of the topical flea treatments.
*Ohio State University. "Cat Fleas' Journey Into The Vacuum Is A 'One-Way Trip'." ScienceDaily 22 December 2007. 24 January 2010
Cat Fleas' Journey Into The Vacuum Is A 'One-way Trip'
ScienceDaily (2007-12-22) -- Homeowners dogged by household fleas need look no farther than the broom closet to solve their problem. Scientists have determined that vacuuming kills fleas in all stages of their lives, with an average of 96 percent success in adult fleas and 100 percent destruction of younger fleas. In fact, the results were so surprisingly definitive that the lead scientist repeated the experiments several times to be sure the findings were correct. ... > read full article