Well, I found one flea on one dog the other day so that meant that everyone was getting bathed. Its alot of work but when I'm not willing to use harsh chemical topical treatments on my dogs that means I must be diligent. One flea can be a ton of fleas very quickly.
In the heat of the hottest month (Sept here in Southern California) I bathed the dogs weekly. Now part of a flea problem can be dry skin so I use a good moisturizer. Fleas drown!!! Who knew? No one from the flea shampoo companies are going to tell you this guaranteed.
When you bathe your dog; make a ring of shampoo and water around their neck and rear end tail area. Do this before you bathe them; this stops fleas from hiding out in nooks and crannies. Then suds up your dog and leave the shampoo on for 5-7 minutes. I use this time to massage my guys and make sure every inch is covered. Slowly you will see the fleas come to the top to try to breath, ha ha don't let them.
Rinse, condition and dry. Vacuum lots and wash your pooches bedding. Sometimes you may have to resort to chemicals but always try alternatives first. I had an outbreak lastyear and used everything until I found out the neighbors dog nextdoor was infested. Great. So now I just spray the fence in hopes of keeping them on their side.