When my dog was just a puppy he wouldn't drink much water either. One trick we used was giving him ice as a treat. Nothing fancy just ice from you freezer. Have him\her do a trick (sit, paw, lay, rollover, ect) and if the dog does it, give him/her a reward, ice! Remember ice is considered water intake so the dog will need to relieve itself after a while. Now my puppy becomes excited when we give him ice. He thinks it's a treat and save a lot of money on treats.
The hard stools may be caused by dehydration so you should encourage the dog to increase his/her water intake. If it has been about a week after the dog has been drinking and you are sure the dog is hydrated but the stools are still hard, I recommend you should see you dog's vet.