Search Menu

You know the modern-day mantra: Stay hydrated! And that goes for your dog too. Make sure there’s plenty of clean, fresh water available, especially during hot weather. But is it possible for your dog to drink too much water?

As important as it is to avoid dehydration, there can be too much of a good thing. Many owners — and even some veterinarians — are unaware that an overabundance of water in a dog’s system can lead to frightening symptoms and even death.

What Is Water Intoxication?

Water intoxication goes by a variety of names, including water poisoning, hyperhydration, and water toxemia. No matter what you call it, this problem can come on suddenly, and the outcome can be fatal.

Here’s what happens when the body is overwhelmed with an excessive amount of water. First, sodium levels outside the cells are depleted, a condition called hyponatremia. In an effort to rebalance itself, the body responds to the low blood sodium by increasing fluid intake inside the cells. Some organs, such as the liver, can accommodate the increased volume of their swelling cells, but others — in particular, the brain, which is encased in bone — cannot.

In humans, water intoxication usually results from drinking too much water after rigorous exercise or competing in water-drinking competitions. (In 2007, a 28-year-old mother of three from Sacramento, California, died after chugging two gallons of water in a radio contest called “Hold Your Wee for a Wii.”) In dogs, excessive water intake often occurs when swimming, diving, or water-retrieving. Even play-biting the stream of water from a garden hose or sprinkler can overload a dog’s system and lead to water intoxication. Because their bodies have to work harder to clear out the excess water in their system, toy and small dogs are at greater risk than larger ones.

Symptoms of Water Intoxication in Dogs

Symptoms of water intoxication include:

  • lethargy
  • bloating
  • vomiting
  • loss of coordination (including stumbling, falling, or staggering)
  • restlessness
  • drooling
  • pale gums
  • dilated pupils
  • glazed eyes

As the pressure in the brain increases and its cells begin to die off, the dog may have difficulty breathing, develop seizures, or slip into a coma.

How to Treat Water Intoxication in Dogs

Because water intoxication involves a lack of sodium, carefully replenishing that important mineral is crucial. Treatment includes the administration of electrolytes. (Moderation is key here, as super-concentrated sodium can cause severe neurological problems.) Veterinarians may administer drugs such as Mannitol to decrease pressure in the brain, as well as diuretics such as Lasix, which help hasten the removal of fluid.

In mild cases, a dog will have a staggering gait, but could eventually recover his internal equilibrium and return to normal. But in severe cases, the brain damage is so advanced that it cannot be reversed, and the dog dies or must be euthanized. If you even suspect that your dog has water intoxication, get to a vet or emergency clinic immediately.

Water intoxication is not widely mentioned in the published veterinary literature and can be misdiagnosed as hypothermia or overexertion. Lower-than-normal sodium levels are a classic sign of water intoxication, but depending on when a vet runs lab work, a dog’s blood-sodium levels may have already started to stabilize, even though the cellular damage is done.

Croatian Sheepdog swimming with a ball in its mouth.
Damir /

What Dogs Are at Risk for Water Intoxication?

As the competitive sport of agility grows in popularity, handlers are discovering that some dogs are at greater risk for water intoxication. Cross-training in swimming pools to help improve conditioning and endurance puts dogs at risk for ingesting too much water, too fast. And the high-energy, high-drive dogs that excel at agility — such as Russell Terriers and Papillons — often have lower fat reserves and higher pain thresholds, prompting them to push through discomfort even after they’ve taken on too much water.

Ironically, breeds that were developed to spend a lot of time in the water, such as Labrador Retrievers and Newfoundlands, tend not to be mentioned in discussions of water intoxication on social media and internet forums. This might be due to the fact that these dogs have been bred to move through the water creating as little surface disturbance as possible in order to best do their work. In short, generations of purposeful breeding has yielded dogs who naturally keep their mouths shut whenever they’re in the wet stuff.

Prevention is Key

Because water intoxication is irreversible in advanced cases, prevention is key. Take note of your dog’s swimming style. If he tends to splash, hold his head low in the water and his mouth open — even slightly — he is at greater risk for water intoxication. Don’t allow your dog to swim or retrieve in water unchecked and take frequent rest breaks. In between swimming sessions, give your dog plenty of opportunities to relieve himself, which helps remove excess fluid.

If your dog is a fetcher, avoid tennis balls and round-shaped toss toys, opting instead for a flatter object, which allows him to better close his mouth around it. Don’t allow him to dive for objects and ditto for biting at the high-pressure stream from a hose.

Now, armed with a little bit of knowledge, you can keep your dog safe while he makes a splash.
Get Your Free AKC eBook

Emergency First Aid for Dogs

Even the most responsible pet owner can't always protect their pet from a sudden accident or illness. Getting your pet immediate medical attention can be the difference between life and death. Download this e-book to learn more about what to do in an emergency situation.
*Turn off pop-up blocker to download
*Turn off pop-up blocker to download