CW, it’s true that carpet aggravates getting rid of fleas. Carpet is nearly the perfect hiding place for fleas and flea eggs.
Regarding getting rid of fleas… I’ve tried over-the-counter stuff, homemade remedies, and professional products (not all at once; don’t want toxin overload). But I have yet to find anything that beats diatomaceous earth, overall, in terms of balancing effectiveness, performance, safety, and cost.
Diatomaceous earth (DE) is non-toxic. Like all fine dust, it’s a good idea not to inhale it. And it’s messy, while you have it down. But otherwise, I’ve found it’s a fantastic way to get rid of fleas. No flea develops resistance (as they can with various poisons). You can treat both your house & pet with it. It’s less expensive than just about anything else I’ve ever tried. And it remains effective, as long as it remains dry.
If I had Berber carpet, I’d sprinkle it heavily all over the carpet, like a carpet freshener. Then I’d go ahead and sweep the rug gently, to brush the DE into and in between the fibers a bit. Where you might have hardwood or tile, you sprinkle down the DE, then gently sweep to the baseboards (to ensure some of the DE makes it under the baseboards). Gentle sweeping only; again, you don’t want to kick up a lot of dust.
I’d do the same for any upholstered furniture; chairs, sofas, mattresses, etc., brushing in the DE. With a mattress, you take off all the bedding, treat with DE, then make up the bed with new linens and wash the used linens in hot water. Also a good idea to wash pillows.
Anyplace where the pet sleeps on a regular basis also needs treatment. So pet beds, etc. need to be treated, too.
The most difficult part for most people is leaving the DE down for 10 days (long enough to break the lifecycle, and to allow any eggs present to hatch out and have the larvae killed by DE). After that, it’s safe to vacuum (where the DE will then kill any fleas living in the vacuum bag). Afterward, discard the vacuum cleaner bag.
You’d want to treat your cats every month or so with DE. Any cat traveling back outdoors is likely to pick up fleas, but if carpet retains some residual DE, there’s DE under baseboards, and the cats are treated with DE monthly, new fleas are likely to be short-lived.
Just my thoughts and experiences; I moved to a non-toxic method after nearly losing one of my cats to over-the-counter products, and spending more than a month’s rent on her recovery. I’ve treated another of my cats with an OTC product, and it burned the skin on the back of her neck. I’ve treated my house and cats with prescription products, spending a lot of money, and still having a few fleas at the end of things. Last, but not least, DE is effective against all insects, not just fleas; any insect with a soft body or exposed joints is susceptible to it. Personally, I’m done with toxic treatments for my cats; it’s just not worth it, to me.
Good luck, whichever products you decide to use! The battle against fleas is a tough one, but it helps if you learn more about their lifecycle (and how to break it). Some info at: http://www.wbvc.bc.ca/external.htm