Water Intoxication in Dogs: How Much is Too Much H2O?

June 12, 2018

By Linda Cole

Responsible pet owners understand the importance of providing their dog with plenty of fresh clean water to drink on a daily basis. Water is a necessary nutrient needed for overall good health. We know that not drinking enough water can cause dehydration and can also indicate an underlying medical condition, but can dogs drink too much water?

Water accounts for about 80% of your pet’s body weight. It flushes waste products from the body, lubricates joints, aids in delivering oxygen throughout the body, cushions internal tissues, helps regulate body temperature, is vital for proper digestion and necessary for a healthy brain. Not getting enough water can cause your dog to become dehydrated, which can be fatal if left untreated. However, ingesting too much water can also be fatal.

Water Intoxication

Water intoxication happens when more water is in body fluids than it can process. This causes sodium levels to become extremely depleted resulting in a shift in electrolyte balance. This is dangerous because sodium maintains muscle and nerve function as well as blood pressure. When excess water dilutes sodium levels it’s in extracellular fluid, which is the fluid outside of cells. As the body tries to balance sodium levels inside the cells while sodium levels outside the cells are depleted, the inflow of water causes cells to swell, including cells in the brain. It can also affect the nervous system.

Dogs at highest risk are those that love to play in a lake or pond retrieving balls and sticks, or diving for toys in a swimming pool. Water intoxication can happen when a dog ingests too much water while having fun. Even snapping at water from a sprinkler or garden hose can put a dog at risk. Some dogs can consume too much water during or after exercising. High energy canines who will jump and dive in water as long as they are allowed to, and dogs who are obsessed with trying to “catch” water from a sprinkler or hose are more at risk.

Any canine regardless of size or breed can develop water intoxication, but symptoms show up more quickly in smaller dogs because it doesn’t take as long for excessive water to build up in their smaller bodies. And dogs that are fit are more prone to water intoxication because they don’t have extra body fat tissue that can absorb extra fluid.

Dogs are much more at risk than cats, but a feline who is deprived of water for some reason, such as accidentally getting locked inside a building for an extended period of time, can end up drinking too much H2O once she’s free.


Water intoxication is a potentially life-threatening condition and can come on quickly, so if you suspect your pet has ingested too much water it’s essential to get him to your vet immediately. Symptoms include loss of coordination, staggering, vomiting, nausea, lethargy, bloating, glazed eyes, dilated pupils, excessive salivating and light colored gums. Severe symptoms include difficulty breathing, collapse, loss of consciousness, seizures and coma.

Thankfully, water intoxication is not a common condition, but pet owners need to be aware of the risk because it can happen. This condition can be treated with IV fluids to replace electrolytes, diuretics (water pills) to increase the amount of water and salt eliminated from the body in urine, and drugs to reduce swelling in the brain. With aggressive treatment some dogs will recover, but too often many dogs don’t.


You can prevent water intoxication by monitoring your dog when he is playing in water. Rough water and pressurized water from a sprinkler or garden hose can cause a dog to ingest a large amount of water in a short period of time. If your dog dives to the bottom of a pool to retrieve toys, is holding a ball, stick or toy while in the water or has his mouth open a lot when in the water, he’s at risk of water intoxication.

There’s nothing wrong with allowing your dog to play in water as long as you have him take frequent breaks to rest. Don’t allow your dog to drink a lot of water after playing hard or exercise. It’s better to have your dog take frequent small breaks for a drink of water to make sure he stays hydrated and doesn’t drink an excessive amount all at once. If you spend time at the beach, make sure to carry fresh water with you. Drinking too much salt water can result in salt poisoning – another life-threatening condition which is the opposite of water intoxication.

Read more articles by Linda Cole

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