You have to also brush it!!! I can't tell you how many times someone brings in a very clean, very fluffy little dog, who is covered in matting head to toe. We call these matts, "bath matts" because that is exactly what causes them, too much bathing,and too little brushing (or more likely, no brushing at all).
This little girl came in after being left in a long trim in October. Her owner had obviously been putting her in the tub weekly since then. Thankfully, she realized the problem and didn't argue when I told her there was only one choice for the haircut today.
In this photo I am holding it up so you can see it's all one huge matted pelt of fur.
There was no other choice but to shave this dog down, trying to brush out that kind of extreme matting, would just be torture to the dog. I don't do that. She was no worse for the wear, and hopefully what I said to the client got through to them. This kind of matting also happens when dogs constantly swim or get wet in the snow. Usually, we see this kind of thing in the spring, but thankfully, even though the temps are really cold right now, her owners didn't wait. Contrary to popular belief, matting will not dissolve in water, the only way to avoid this mess is to brush your dog out after each bath. (preferably before AND after).