If your dog suddenly drinks excessive water than you must have to consult your vet. Excessive drinking may be caused due to diabetes or any thyroid problems. It may be due to urinary tract infection or pyometra.
It is advisable to consult the doctor to diagnoses it properly. There are other reasons also. If your dog eating the dried food than dog require more water.
It is essential to maintain the content of the water in the food if your vet does not give any sign of diseases. It is important to know that the how much water you need to server to your dog. You can get information about the water in the diet so that you can serve it as suggested by the vet.