It's almost *never* a good idea to limit the water of an over-drinking dog bc of the possibility they could have Diabetes Insipidus (not diabetes mellitus). Limiting the water of a dog who has DI can easily be fatal.
Most dogs self regulate their water intake. However, when there is truly polydipsia (frequent drinking) and polyuria (frequent, dilute urination) - there is a reason for it. Even if it's just excessively hot/warm in your area right now...that would still be a reason why some dogs drink more, cyclically.
Dogs who eat kibble will drink more than dogs who eat raw or canned. That said, that doesn't mean that kibble-eaters' urine is expected to be more dilute. It just means they need more water in proportion to fulfill digestive needs.
Given your kiddo's age, it's hard to imagine their is something like D.inspidus or whatever...but if you truly do see PD/PU....it's something to keep pushing in terms of getting a diagnosis. I too was told Wylie's former PD/PU was "nothing"....well, after finally finding new vets....turned out Wylie has Atypical Cushings and hypothyroid.
Some reasons for PD/PU:
Urinating Frequently (Polyuria) Can Be a Sign of Serious Disease in Pets