BELIEVE it or not!
Allow it to sit for a minute or two, as many as 5 on heavily infested animals, and then rinse. I use my recirculating washer to rinse with as it also bathes the pet for me using the existing shampoo, which cuts down on water consumption, shampoo usage and time. I simply put fresh water in the tub while the pet is sitting and rinse it using the system after it has sat the required amount of time. This reduces the need for rinsing, washing and then rinsing again.
I then rinse and using a soothing shampoo rebathe the dog to ensure that all the soap is removed and the skin is treated to prevent itching. Conditioner can be applied afterward if needed, but rarely if ever do I have to add this after I am finished.
Now, I know that Dawn is controversial, but honestly I have never had an issue using it. It it makes you uncofortable then use ANY shampoo labled for dogs. It will work, it just might take longer to kill the fleas than the Dawn does.
I live in an area where fleas are the new accessory and every dog has some it seems like. Some days EVERY dog does. By using Capstar (with owners permission) on really infested dogs and using the shampoo killing method we have no fleas in the shop.
I also do not use bombs or sprays on the floors. Once a week or so we set flea traps using a small lamp over a bowl of water left on all night. I put a drop of dish soap in the water to break the surface tension of the water and once the fleas jump towards the light they fall into the water and drown. I usually find two or three in the bowl. That is the safest way I have ever seen to kill fleas in the shop or house environment. You can also buy a flea trap that is made to trap fleas on sticky paper. they are as effective as the bowl of water, just more expensive.
Hopefully this helped a little bit in the flea eradication program we must all have in our shops and vans. Saftey and health first.