Just like ourselves, dogs depend on water for nearly every vital function in the body. It supports healthy digestion, cushions joints, regulates temperature, and keeps the organs ticking along nicely. When fluid levels drop too low, things can go downhill quickly.

Dehydration in dogs can creep up faster than you'd expect. That’s why it’s so important to recognise the early signs and understand what you can do to help.

Why Dehydration in Dogs Is More Serious Than You Think

Even a mild fluid loss can disrupt how your dog’s heart, kidneys or digestive system works. In more severe cases, dehydration can lead to organ failure or even become fatal.

Puppies are especially vulnerable — not only do they have less body mass to work with, but they also burn through energy at a rapid pace.

Spotting the Signs of Dehydration

Here are the classic signs to keep an eye on:

• Skin Tent Test: Gently pinch a small bit of skin over your dog’s shoulder. If it doesn’t spring back straight away, that’s a red flag.

• Dry, Tacky Gums: Healthy gums should be moist and pink. If they’re sticky or pale, it may signal dehydration.

• Thick Saliva: A ropey or stringy texture means your dog isn’t producing enough fluids.

• Sunken Eyes: Loss of volume behind the eyes makes them look hollow.

• Panting or Lethargy: Heavy breathing without exertion and loss of energy are big signs your dog isn’t feeling right.

These symptoms may be subtle at first but can escalate if fluid isn’t replaced quickly.

Common Causes of Dehydration

1. Overheating and Heatstroke

Dogs can’t sweat like humans — they release heat mostly through panting. Add a warm Irish day (or a stuffy car), and you’ve got a recipe for trouble. Flat-faced breeds like Bulldogs and Pugs are especially at risk.

2. Persistent Vomiting or Diarrhoea

If your dog has a bout of stomach upset, they're losing fluids faster than they can take them in. This is common with parasites or tummy bugs.

3. Chronic Conditions

Dogs with kidney disease, diabetes, or Cushing’s disease often drink more but still wind up dehydrated due to how these conditions impact fluid balance.

4. Lack of Water Access

It sounds obvious, but sometimes a bowl is knocked over or left empty longer than expected. Always keep bowls topped up — inside and out.

5. Foreign Object Blockage

Young dogs especially tend to chew or swallow things they shouldn’t. A stuck toy or sock can block the gut, making it impossible for water to pass.

What About Puppies?

Puppies can become dehydrated in a matter of hours. Besides the above, be alert to:

• Parvovirus, which causes bloody diarrhoea and is highly contagious. Ensure your puppy is up to date on vaccines.

• Intestinal worms, especially roundworms or hookworms.

Check out our [Puppy Care section] to learn about safe vaccination schedules and parasite prevention.

What You Should Do If You Suspect Dehydration

• Mild symptoms? Offer small amounts of water frequently (1 tsp every hour for small dogs, 1 tbsp for larger ones). Avoid letting them gulp it all at once.

• More severe symptoms? If there’s vomiting, diarrhoea, or they haven’t eaten or urinated in 24 hours — call your vet.

Be ready to share info like how long symptoms have been present, what your dog’s been eating or doing recently, or if they’ve had access to heat or something toxic.

How Vets Treat Dehydration

A vet will assess how serious it is with a full exam and tests like bloodwork, urine analysis or abdominal x-rays. Treatment typically involves:

• Subcutaneous fluids (under the skin)

• IV fluids (for severe cases)

The underlying cause also has to be addressed, whether it’s an infection, heatstroke or a blocked bowel.

Preventing Dehydration

Some practical ways to keep your dog well-hydrated:

• Top up water bowls regularly, especially outdoors.

• Bring a collapsible bowl on long walks.

• Feed canned food to boost moisture intake.

• Monitor dogs on medications that increase urination or thirst.

Dogs should drink about 1 ounce of water per pound of body weight per day. A 10kg dog (22 lbs) should have roughly 2.5 cups of water daily.

If your dog is very active, older, on medication, or has health issues, they may need more.