Signs of Dehydration in Dogs: How to Spot It and What to Do

Dehydration in dogs is more common than many owners realise - and the signs can be subtle until they become serious. Water plays a role in almost every biological process in your dog's body, from regulating body temperature to lubricating joints. When your dog doesn't drink enough, the effects show up faster than you might expect, particularly in their mobility and joint comfort. In this guide, we cover the key signs of dehydration in dogs, how to check at home using the skin tent test, and practical ways to keep your dog hydrated and their joints healthy year-round.

How much water should a dog drink per day?

As a general guide, dogs need approximately 50ml of water per kilogram of body weight per day. A 10kg dog needs around 500ml; a 30kg dog needs approximately 1.5 litres.  
This increases significantly during hot weather, after exercise, or if your dog eats  
dry kibble rather than wet food. If your dog is consistently drinking much more or much less than this, consult your vet.

Why Hydration Matters for Your Dog's Health 

Exactly as it is in us, water is involved in almost every biological process in your pet’s body. It helps:

• Regulate body temperature

• Transport nutrients around the body

• Support circulation

• Aid digestion

• Lubricate tissues and joints

• Maintain healthy muscle function

Pets naturally lose water throughout the day through panting, urination, breathing, and physical activity. But when that sun comes out and temperatures rise, fluid loss increases significantly as pets battle to maintain their body temperature. As they are naturally well insulated with fur, when the temperature rises, dehydration can develop surprisingly quickly, and pets don’t always compensate enough by drinking more, so encouraging them to increase their water intake is vital to their health in warmer weather. 

How Dehydration Affects Your Dog's Joint Health 

We think of stiff joints being affected by cold weather, and you might notice your pet slowing down more in the winter. But surprisingly, the warm weather and dehydration can also affect your pet’s mobility and joint health, and hydration is key to keeping your pet mobile during the summer. But how does hydration impact mobility?

Synovial fluid thickens when dehydrated

Synovial fluid is the lubricant in your pet’s joints. It helps to keep joints “oiled” and moving freely. Water is the main constituent of synovial fluid, and when properly hydrated, it is a gel-like substance that allows joints to move smoothly. When your pet is dehydrated, water is rationed, their bodies produce less synovial fluid, and the synovial fluid thickens, meaning joints move less freely and the shock-absorbing capabilities of synovial fluid are reduced.

Cartilage cushioning decreases during dehydration

Cartilage, the cushioning coating the ends of your pet’s bones, is made up of 80% water. Normally, cartilage protects the ends of the bones and acts as a cushion between them, helping joints glide smoothly and serving as shock absorbers. When your pet becomes dehydrated, the cartilage loses moisture, making it less resilient to impact and more prone to compression and wear and tear.

Signs of Dehydration in Dogs 

Early signs of dehydration can be subtle, while later signs are very obvious. Watch for:

• Excessive panting

• Dry or sticky gums

• Lethargy

• Reduced energy levels

• Sunken eyes

• Thick saliva

• Loss of skin elasticity

• Reluctance to exercise or continue walking

How to check for dehydration – The Skin Tent Test

An easy way to check your pet’s hydration status is the “skin tent test”. Gently pull the skin at the scruff of their neck up. It should return to its normal position almost immediately. If it takes a few seconds, your pet is dehydrated. 

If your pet appears weak, distressed, or severely dehydrated, seek veterinary advice immediately.

If your pet is at risk of dehydration, it’s also important to keep them cool. Learn ways to keep your pet cool this summer here.

When to Contact Your Vet

Mild dehydration can often be managed at home by encouraging your dog to drink small amounts regularly. However, contact your vet immediately if your dog:

• Is showing moderate to severe dehydration symptoms (sunken eyes, thick saliva, loss of skin elasticity)
• Is vomiting or has diarrhoea alongside dehydration signs
• Is a puppy, senior dog, or has an underlying health condition
• Shows no improvement after increasing water intake
• Appears weak, confused, or is unable to stand 
  

Severe dehydration requires veterinary treatment including fluid therapy and should not be managed at home.

How to Keep Your Dog Hydrated: 7 Practical Tips 

Water bowls everywhere

Have water bowls in multiple locations around your house and outdoor space. This way, your pet has easy access to fresh water, no matter where they go.

Keep your pet’s water fresh

It’s easy to forget about a water bowl, and quickly the water becomes warm and a little musty. Studies have shown that pets prefer cool water, so make sure to change it regularly. 

Little and often

Encourage your dog to drink little and often, particularly after exercise or periods of excitement. Drinking large amounts of water too quickly can sometimes lead to regurgitation or stomach discomfort. Offering smaller amounts at regular intervals helps promote safe hydration while reducing the risk of digestive discomfort.

Take water out with you and your pet

We remember to take water out for ourselves when the weather is warm, so don’t forget water for your pet. You can pour it into a collapsible bowl or use a specially designed “pet bottle” with a built-in bowl. 

Use pet water fountains

Lots of pets drink more water when they have access to running water. Many cat owners report that their cat loves to drink from a running tap. Specially designed pet water fountains are a fantastic way to encourage your pet to drink more when it’s warm. 

Feed water-rich food and snacks

Adding water to your pet’s diet is a quick and easy way to increase their water intake. Add a little water to their kibble, try offering them bone broth, or specially formulated oral rehydration solutions as a quick way to add water to their food. You could also offer water-rich snacks such as watermelon or cucumber. 

Adjust your exercise times

Too much exertion in the heat increases the likelihood of dehydration, but also hugely increases the risk of heatstroke. Adjust your walk times to avoid the warmest parts of the day, and learn when it’s too hot to walk your dog here. 

Supporting Your Dog's Joint Health Year-Round 

Hydration is one important part of a broader approach to keeping your pet’s joints healthy. Alongside regular low-impact exercise and maintaining a healthy weight, good hydration habits can help pets stay active and comfortable.

Adding AntinolⒸ Joint Care Pro to their daily routine will support their joint health and mobility no matter what the weather throws at us. Backed by over 25 years of scientific research and containing highly concentrated green-lipped mussel oil, rich in the full spectrum of omega-3’s- it’s joint care you can trust throughout your pet’s life. 

Whether it’s daily walks, countryside adventures, agility training, or simply enjoying playtime in the garden, healthy movement starts with supporting the body from the inside out- whatever the weather.

Enjoy your summer with AntinolⒸ Joint Care Pro

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