You have to treat your pets as well as your carpet. I have a white cat and his fleas have been so bad it looked like he got his nose into a pepper shaker! Little black specks. I picked them off with tweezers and treated him again.
I wish I could dip my cats. That would be quicker, but I can just imagine trying to do a flea dip with a cat. I'd have to wear leather gloves up to my armpits.
I've heard that sprinkling the carpets with baking soda before vacuuming helps trap the fleas. I don't know, but I don't suppose it would hurt anything. Baking soda is cheap so it might be worth a try.