Why Is My Pet Drinking So Much Water?

If your older pet is suddenly drinking more water than usual, and the weather hasn’t been particularly warm, it could be a sign that something deeper is going on with their health.

Have you noticed they’re waking you up during the night, asking to go outside more often? Have there been unexpected puddles or damp bedding in the morning? These behaviours can be more than just inconvenient — they can signal that your pet might be unwell.

Increased thirst and urination can be caused by several different conditions, most of which can be managed with early diagnosis and the right treatment. But first, we need to get to the bottom of what’s going on.

Step One: The Detective Work Begins

The first step is a thorough consultation. We’ll ask you quite a few questions about your pet’s recent behaviour, appetite, energy levels, toileting habits, and more. You might find our questions a little unusual, but every detail helps us build a picture of what might be going on.

Then we perform a complete physical examination. This allows us to check your pet's body condition, hydration, organ size, and other physical signs that may give us more clues.

Step Two: Blood and Urine Testing

The next step is to test your pet's blood and urine. These tests provide a treasure trove of information:

• Urine test: We check how concentrated the urine is, whether there's sugar present, signs of infection, or other abnormalities. Even a small sample can tell us a lot about your pet’s overall health.
• Blood test: We look at red and white blood cells to check for signs of infection, anaemia, or dehydration. We also evaluate organ function, including the kidneys, liver, and pancreas.

From there, we can determine if further, more detailed testing is needed.

What Conditions Could Be Causing This?

Let’s walk through three common conditions we investigate when a pet starts drinking and urinating more than usual.

1. Diabetes Mellitus (Sugar Diabetes)

Yes, pets can get diabetes too! In both dogs and cats, diabetes happens when there isn’t enough insulin, or the body doesn’t respond properly to it. Insulin helps move sugar (glucose) from the bloodstream into cells for energy.

To diagnose diabetes, we check for high sugar levels in both the blood and urine. Sometimes, we use a special test called Fructosamine, which gives us an average blood sugar level over several weeks — especially helpful in cats, who can spike their sugar just from the stress of visiting the vet.

Diabetes can be managed effectively with medication and a consistent routine. There is now even a Diabetic Food for cats which can in many cases replace the ‘old’ insulin injections.

The GREAT news is that in the last month, two NEW products have been released to help treat Diabetes in dogs and cats. These are GAME CHANGERS……

Diabetes is now more manageable than ever before. One key to remember is this; communication between you and our team is also key to managing this condition well.

2. Kidney Disease (Renal Failure)

The kidneys are vital for filtering waste from the blood. But unfortunately, once parts of the kidney (called nephrons) are damaged, they don’t repair themselves. Over time, with age or due to infections, toxins, or stones, the kidneys lose more and more function.

Early kidney disease often leads to increased drinking and urinating, as the kidneys try to compensate. But once function drops below 25%, waste builds up in the body, leading to symptoms like:

• Bad breath
• Weight loss
• Reduced appetite
• Vomiting or ulcers in the mouth

We diagnose kidney disease through physical exams and blood and urine testing. There is no cure for chronic kidney failure, but with early detection, special diets (like Hills KD and Royal Canin Renal), some newer medications, hydration support, and ongoing care, we can help your pet live more comfortably for longer.

3. Cushing’s Disease (Hyperadrenocorticism)

This condition involves the adrenal glands producing too much cortisol. It often develops slowly and can go unnoticed for years.

Alongside excessive drinking and urination, pets with Cushing’s often show signs like:

• Constant hunger
• A pot-bellied appearance
• Hair thinning or skin changes
• Lethargy or excessive panting

It is more commonly diagnosed in dogs than cats. Again, early detection through screening blood tests makes a big difference. Treatment depends on the severity, but with monitoring and medication, pets with Cushing’s can still live happily for many long years and most will even have regression of those clinical symptoms described above.

What Should You Do If You Notice Changes?

If your pet is suddenly drinking more water, urinating more often, or having accidents in the house, don’t dismiss it as ‘just getting older’. These signs are worth checking out.

The earlier we detect the cause, the more options we have to help.

Let’s Keep Them Feeling Their Best

At Highlands Veterinary Hospital, we know how much your pets mean to you. They’re family. We’re here to help them stay healthy and happy for as long as possible.

If you’ve noticed your pet drinking more water than usual, call us today on (02) 4872 1144 or book an appointment online.

Even small changes can mean something significant, and we're here to guide you every step of the way.