Dehydration in Dogs: Signs, Causes and Rehydration

By Tailwisp Editorial TeamUpdated October 17, 20263 min read

Water is essential to every body system, and dogs can become dehydrated quickly during illness or heat.

Signs

• Dry, sticky or pale gums
• Thick, ropey saliva
• Sunken eyes
• Loss of skin elasticity
• Lethargy and weakness
• Reduced urination and dark urine
• Fast heart rate
• Loss of appetite
• Collapse in severe cases

Simple checks

1. Skin tent test: lift the skin over the shoulder blades and release. It should snap back within a second or two. Slow return suggests dehydration, though thin, older or obese dogs may give misleading results.
2. Gum moisture: gums should be wet and slippery.
3. Capillary refill: press a gum and count seconds until color returns. See dog normal vital signs.
4. Water intake and urination: note changes.

Common causes

• Vomiting and diarrhea. See dog vomiting causes and dog diarrhea
• Heat and heatstroke. See dog heatstroke
• Fever and infection
• Kidney disease and diabetes. See kidney disease in dogs
• Not drinking, from illness, pain or travel
• Excessive exercise
• Blood loss and burns

How much water do dogs need?

A common guide is about 1 ounce per pound (about 65 ml per kg) of body weight per day, but needs vary with diet, weather and activity. See how much water should a dog drink.

What to do at home

If your dog is bright and has mild signs:

1. Offer small amounts of water frequently rather than a big bowl.
2. Try ice chips or unsalted broth made for dogs, if your vet agrees.
3. Offer wet food to add fluid.
4. Keep him cool and rested.
5. Monitor closely and call your vet if he does not improve.

Do not force water into the mouth, since it can enter the lungs.

When to see a vet

Seek veterinary care for moderate or severe signs, repeated vomiting, diarrhea, lethargy, puppies, seniors, small dogs and dogs with chronic disease. See dog emergency warning signs.

Veterinary treatment

Vets give intravenous or subcutaneous fluids with electrolytes, treat the underlying cause and monitor bloodwork. Dogs often improve quickly, but those with organ disease may need ongoing care.

Electrolyte solutions

Some vets suggest unflavored electrolyte solutions, but human sports drinks can be too sugary or salty. Ask for guidance on products and amounts.

Prevention

• Provide fresh water at all times
• Carry water on walks and hikes
• Limit exercise in heat
• Treat vomiting and diarrhea early
• Watch senior dogs and those with chronic illness
• Use wide, clean bowls and wash daily

See dog hot weather safety.

Common mistakes

• Waiting too long with vomiting or diarrhea
• Relying solely on the skin tent test
• Forcing water
• Using sports drinks without advice

Troubleshooting

• My dog will not drink: try different bowls, wet food or warm water.
• Gums seem tacky: call your vet.
• My puppy has diarrhea: seek care promptly.

A simple plan

1. Check hydration.
2. Offer small sips.
3. Call your vet if unsure.
4. Treat the cause.

Real-life examples

A hiking dog recovers after shade, water and rest. A puppy with gastroenteritis needs hospital fluids. A senior dog's dehydration reveals kidney disease. Early care helps.

Be proactive

Frequent small drinks and awareness prevent most problems.

Dehydration and heat

Hot weather, hard exercise and hot cars are major causes. Carry water on every outing, offer drinks before your dog is panting heavily and rest in shade. Dogs left outdoors need shaded, tip-proof bowls refreshed through the day, since warm, dirty water discourages drinking.

Encouraging a dog to drink

Some dogs drink more from a fountain, from several bowls around the house or when water is lightly flavored with a spoonful of low-sodium broth made for dogs. Wash bowls daily and try a different material if your dog avoids his bowl. Wet food and ice cubes add fluid without effort.

The takeaway

Dehydration develops fast. Check hydration, give small sips and call your vet for moderate signs.

This article is general educational information, not veterinary advice. Every dog is different. If your dog is unwell, or you are unsure about a symptom, diet change or medication, contact your veterinarian.