Raising very young puppies is a major responsibility that requires you to be concerned about issues ranging from sanitation and nutrition to hydration requirements. Until a puppy reaches weaning age, however, Mamma is the answer to most of the questions.
Nursing
Until a puppy reaches weaning age, he doesn't need water or anything else, other than milk straight from Mamma. The mother's milk gives the puppy not only all of the vital nutrition he needs to thrive, but all the hydration as well. If Mamma hasn't started encouraging her litter to begin eating solid foods, then the puppies don't need water. In cases where the mother dog is not in the picture, you can easily nourish a puppy with formula and a commercial, canine-specific milk replacer. If possible, you also can try to find a lactating foster mother.
Weaning
Mother dogs usually start weaning their little ones when they're between 3 and 4 weeks old. The process is gradual, and usually continues until the puppies reach approximately 8 weeks. Toward the end of weaning, the puppies will be eating mostly solid meals with just occasional nursing. They'll also be drinking water.
Water
Water is a crucial nutrient for dogs, just as it is for humans. If a puppy is 4 weeks old and has already started eating solid food, then it's important to supply water as well. Much hydration should be supplied in the food, but it's vital to keep a fresh water supply easily accessible. Pour fresh, clean, cool water into a shallow, spill-proof container, and keep it within reach of the weaning puppies at all times.
Mother Dog
Although there's no need to supply water to nursing puppies, it is vital to ensure that the nursing mother has a plentiful supply of fresh water at all times. Consult your veterinarian regarding proper nutrition for a lactating dog. Along with ample water, a nursing mother dog will need sufficient calories to satisfy her own nutritional needs and those of her puppies, possibly with added phosphorus and calcium.