I don't know what to tell you exactly...there may or may not be a problem. Newborns should have 6-8 heavy soaked diapers a day. This is what every doctor will tell a new mom, but usually if that is ok, doctors don't worry about it as a matter of routine at 7 months. This is just a measure of knowing how much fluid intake they have. Remember that what goes in must come out.
When I have researched for stories and information on this topic, it seems that if you are really worried that your baby has some bigger problem like diabetes or such like (which I think improbable) you can take him to a doctor, and with his advice might need to take him in for a urinalysis and possible blood testing. Some doctors tend to take things way too far, so please be careful.