Many loving, good-hearted pet owners spend a lot of time and energy making sure their pet has a healthy diet considering brands, comparing labels, debating moist-versus-dry, and consulting their veterinarian. In all the hubbub, they sometimes forget that an ever-present bowl of clean water may be the most important part of their pet's diet.

Why is it important?
In pets, as in people, water makes up the majority of the body about 80 percent. By allowing substances to dissolve and be carried through the body, it provides a basis for nearly all of the processes and chemical reactions that keep the body running, including digestion and circulation. It helps the body to filter out waste, and it regulates body temperature through evaporation. Dehydration, a lack of water in the body can cause serious problems, including kidney and heart damage.

What should I do?
As vital as water is, it's relatively easy to provide. Just make sure your pet has a clean bowl (or bottle, in the case of some smaller animals) of fresh water at all times. A general rule of thumb is that most animals should have about 28 milliliters (or one fortieth of a liter) of water per pound of body weight per day. A forty-pound dog needs about a liter of water every day; a ten-pound cat needs about a quarter of a liter. You don't really need to spend time crunching the numbers, though most healthy animals that have access to clean water will drink enough to keep them hydrated.
If you're worried that your pet isn't drinking enough, or you see signs of dehydration like depression, sunken eyes or dry gums, take your little furry guy to the veterinarian. If your pet's dehydrated, your veterinarian can give him intravenous fluids and find out what caused the problem.

Common pitfalls
Though water seems like a simple enough subject, a few common problems can leave pets high and dry:
**The water bowl or water bottle needs cleaning every day. Bacteria that you can't see can grow in a bottle or bowl, giving the water a funny taste and discouraging your pet from drinking. Even worse, some kinds of bacteria can make animals sick. Develop the habit of giving the bowl a quick scrub with dish soap before you fill it in the morning. Pocket pets' hanging water bottles can be particularly hard to get clean; you may want to buy a long, narrow scrub brush that can fit through the bottle's neck and clean the inside.
**Dogs and cats that are left alone for long periods can easily knock over their water bowls. Try buying a bowl with a wide, weighted bottom. You may also want to leave more than one bowl around the house: one in the bathroom, for example, and another in the kitchen.
**Water evaporates faster than you may realize, particularly on warm days. Check water bowls a few times a day, especially in the summer. If your pet's outside on a very hot day, check the water every hour.
**You may think you're helping your pet out by setting out a big bucket filled with water, but once the bucket's half empty, he may not be able to get to the water anymore. Cats and small dogs could even fall in while drinking. Before you use a water bucket, make sure your pet's neck is long enough to allow him to drink from the bottom of it.
**Dogs that are chained up can easily wind the chain around a tree, a post, or even their own legs. With a tangled chain, they can't get to their water bowl. If you have to leave your pet chained outdoors, check him often.
**Lots of dogs and cats see the toilet as a big water fountain. Keep the toilet lid closed, because the bacteria in toilet water can make animals sick and, as with large buckets, cats and small animals can fall in while drinking. Even the best of us can forget to close the lid every once in a while, though, so don't use drop-in cleaners that release chemicals into the toilet bowl. These chemicals may be toxic.
**Some exotic animals, particularly amphibians like frogs and salamanders, can't or won't drink water from a bowl. These guys need a drip watering system, which drips or sprays temperature-controlled moisture into a cage for a few hours at a time. To select the right watering system for your exotic pet, consult your veterinarian.
Reptiles often need a long, shallow dish of water in their cages. They use this water both to drink and to soak in, so it needs to be checked several times a day for dirt or fecal matter.
**Just like you, pets need more water when they're exercising. If you take your dog out for a long walk or run, bring along some water for him. Most pet stores sell light, collapsible travel water bowls that are easy to carry.
As long as you keep an eye on your pet and make sure his water is fresh and plentiful, you shouldn't have a problem. If you have any concerns about providing water for your pet, consult your veterinarian.