Why Is My Dog Drinking So Much Water?

When Is My Dog Drinking Too Much Water?

Drinking excessively is also known as polydipsia(PD) and passing increased amounts of urine is called polyuria(PU). These two things often go together and vets will often talk about this as PU/PD.

Excessive drinking is defined as a dog drinking more than 100 millilitres (ml) of water per kg of body weight per day. If you are in doubt, and your dog is otherwise well, you can start by measuring your dog’s water intake.

Fill your dog’s water bowl and measure how many ml of water you have to add to achieve the same level in the bowl 24 or 48 hours later.

Divide the average daily ml added with your dog's weight in kg. For example, you have added 1800ml of water to the bowl over 24 hours and your dog weighs 16kg.

1800ml/16kg = 112.5ml/kg/24 hours - this is excessive. 

Knowing the water intake will be useful for your vet.

Why Is My Dog Drinking So Much Water?

There are several medical reasons that could cause a dog to drink excessively. Here are some of the most common:

• Diabetes – Causes increased thirst, urination, and appetite, often with weight loss.
• Kidney disease – The kidneys struggle to retain fluids and this is passed in the urine.
• Cushing’s syndrome – A hormonal disorder that leads to increased thirst.
• Urinary tract infections
• Pyometra - uterine infection in unspayed females, typically 4-8 weeks after a season.
• Medications – Some drugs, such as corticosteroids, can increase thirst.

What goes in must come out 

Dogs can only get rid of significant amounts of fluids via respiration, vomiting or by passing urine or faeces. Therefore, if your dog is drinking more without any other changes, such as hot weather, vomiting or diarrhoea, then it is highly likely that your dog will be passing larger volumes of dilute urine as well. 

Urine analysis is often required to identify the cause of your dog's increased water intake and it is often helpful to bring a fresh urine sample in a clean container to your vet appointment. 

Signs To Look Out For

Depending on the underlying cause, dogs that drink too much water may also show any of these signs:

• Lethargy
• Vomiting or diarrhoea
• Urinary incontinence
• Reduced or increased appetite
• Enlarged abdomen
• Abdominal pain or discomfort
• Vaginal discharge in female dogs

Please seek veterinary advice if your dog is drinking too much or if you see any of these signs.

Diagnosis – What the Vet Will Check?

To find the reason for your dog’s increased drinking, a full clinical examination by your vet is needed, as well as additional tests. The type and number of additional tests varies depending on the findings seen on the clinical exam, the signs you have seen and your dogs age, sex and breed.

Common tests include urine analysis, blood tests, and sometimes imaging like ultrasound or X-rays. Hormone tests may also be needed to diagnose diseases like Cushing’s syndrome.

When Should I Contact a Vet?

Contact your vet if your dog:

• Suddenly starts drinking more than usual without a good reason
• Has a reduced appetite
• Seems lethargic
• Has a vaginal discharge
• Is older and has new or unusual symptoms
• Pants excessively or appears to be in pain
• Urinate more or with increased frequency

Treatment Depends on the Cause

Treatment varies based on the diagnosis:

• Diabetes – Is treated with insulin and a special diet.
• Kidney disease – Is managed with a special diet, fluids, and medication.
•  Pyometra – Usually requires surgery to remove the uterus.
• Cushing’s disease – Is treated with medication.
• Urinary tract infections  – Usually require antibiotics and/or anti inflammatory medications.

Prognosis – What to Expect

The outlook depends on the underlying cause. Acute illnesses like pyometra can be fatal if left untreated but often have good outcomes with prompt care. Chronic diseases like diabetes or kidney failure can often be managed to ensure a good quality of life. Early diagnosis improves the chances of successful treatment.