By Dial A Vet Veterinary Team
Last updated: 11 November 2026
If your senior dog is suddenly emptying the water bowl, asking to go out at night or having accidents inside, it is worth paying attention. VCA notes that the earliest clinical signs of chronic kidney disease in dogs are increased water consumption and urination, and the same change is one of the most common signs of Cushing's disease. Drinking more is not a diagnosis, but it is often an early, useful clue that something inside has changed.
Key takeaways
- Increased thirst (polydipsia) and increased urination (polyuria) usually go together.
- Common causes in older dogs include kidney disease, Cushing's disease, diabetes, liver disease, high blood calcium, some cancers and certain medicines (VCA).
- In an undesexed female, increased thirst after a recent season can mean pyometra, a life-threatening uterine infection.
- Measuring how much your dog drinks over 24 hours helps your vet judge how serious it is.
- Blood tests and a urine test are the usual first step.
- Related: kidney disease in dogs, Cushing's disease in dogs, diabetes in dogs.
When to see a vet urgently
Go to your nearest vet or emergency vet clinic the same day if increased thirst comes with:
- Vomiting, refusing food, or weakness and lethargy
- A swollen belly or vaginal discharge in an undesexed female dog
- Collapse, trembling or confusion
- Rapid weight loss, or a sweet or unusual smell to the breath
- Very little urine despite drinking, or straining to urinate
If your dog seems well otherwise, book a vet visit within a few days and start measuring water intake now.
Normal thirst versus too much
Dogs naturally drink more in hot weather, after exercise and if they eat mostly dry food. What matters most is a change from your dog's own normal. Signs that thirst may be abnormal include refilling the bowl much more often, drinking from unusual places like the toilet or shower, needing to toilet overnight, and new accidents in a house-trained dog. Do not restrict water to stop the accidents. A dog with increased urine loss needs that water to stay hydrated.
Common causes in older dogs
VCA lists the most common conditions linked to increased thirst and urination:
- Kidney disease. VCA explains that early in chronic kidney disease the kidneys make more dilute urine, and dogs drink more to compensate. At least two-thirds of kidney function is lost before clinical signs appear, so thirst may be the first thing you notice.
- Cushing's disease (hyperadrenocorticism). VCA describes increased appetite, thirst and urination as the most common signs, often with a pot-bellied look, panting, thin skin and hair coat changes.
- Diabetes mellitus. A dog that is eating well but losing weight may have diabetes, VCA notes.
- Pyometra. An infected uterus in undesexed females. VCA mentions a history of being in season as a clue.
- Liver disease, high blood calcium and some cancers, including lymphoma.
- Medicines. VCA lists corticosteroids, anti-seizure drugs and diuretics as examples. Tell your vet about every medicine and supplement your dog takes.
- Rarely, diabetes insipidus or a behavioural habit called psychogenic thirst.
What your vet will do
VCA describes a stepwise approach. It starts with a full history and physical examination. Then the usual screening tests are:
- A complete blood count, which looks at red cells, white cells and platelets
- A biochemistry panel, which checks kidney and liver values, blood sugar and electrolytes
- A urinalysis, which shows how concentrated the urine is and looks for infection, sugar and protein
Depending on the results, your vet may recommend further tests such as hormone tests for Cushing's disease, a urine culture, x-rays or an ultrasound.
How you can help at home
- Measure intake. VCA says it helps to measure how much your dog drinks in 24 hours. Fill a jug, top up the bowl from it, and note what is left at the end of the day.
- Bring a urine sample. Collect a fresh morning sample in a clean container if your vet asks.
- Write down other changes. Appetite, weight, coat, panting, accidents and energy all help.
- List all medicines, including flea, tick and joint products.
- Keep fresh water available at all times.
Treatment depends on the cause
There is no single treatment for increased thirst. Kidney disease is managed with diet and supportive care. Cushing's disease and diabetes usually need ongoing medicine and monitoring. Pyometra generally needs urgent surgery. Your vet will explain options once they know the cause. Do not start supplements or change diets for a thirsty dog before tests are done, as this can affect results.
FAQ
Is it normal for old dogs to drink more?
A small change in hot weather can be normal, but a clear increase in a senior dog should be checked, because kidney disease and hormone conditions are common causes.
Should I limit my dog's water?
No. Restricting water can cause dehydration, especially if your dog has kidney disease.
Can dry food make my dog thirsty?
Dogs eating only dry food drink more than dogs eating wet food, but a sudden change on the same diet deserves a vet visit.
Is increased thirst an emergency?
Not always. It becomes urgent with vomiting, lethargy, not eating, a swollen belly or vaginal discharge in an undesexed female.
Talk with a vet
If your older dog is drinking more and you want help deciding how urgent it is, book a video consult with Dial A Vet's real vets and vet nurses. We can help you plan what to measure and what tests to ask about, with same-day and extended hours. We help with dogs and cats. Book a Dial A Vet consult.
References
- VCA Animal Hospitals. Testing for Increased Thirst and Urination.
- VCA Animal Hospitals. Chronic Kidney Disease in Dogs.
- VCA Animal Hospitals. Cushing's Disease in Dogs.
Disclaimer: Educational only. This page does not replace an examination or advice from your own veterinarian. If you are worried about your pet right now, contact your local vet or nearest emergency vet clinic.