By Dr Duncan Houston
Refilling the water bowl more often or finding larger litter clumps can be an early clue that something has changed. It is easy to blame hot weather or age, but a persistent increase deserves attention.
The first distinction is between passing more urine overall and repeatedly trying to pass small amounts. Those patterns point towards different problems.
Quick Answer
Polyuria means increased urine volume, and polydipsia means increased thirst. Kidney disease, diabetes, hormonal disorders, medicines and other illnesses can cause both. Keep water freely available, record the change and arrange a veterinary examination. Repeated straining with little urine, severe illness or collapse needs urgent care.
More urine or more attempts?
A dog producing large puddles or a cat making unusually large clumps may be losing more water through urine. Frequent squatting with a few drops instead suggests irritation, pain or possible obstruction. Leaking urine while asleep is another pattern and may occur without a major increase in urine production.
These patterns can overlap. A short video and observations of actual output are more useful than describing every urinary change as an accident.
What can cause increased drinking?
| Context | Possibilities | Next step |
|---|---|---|
| Hot weather, exercise or a drier diet | Increased water need may be appropriate | Compare with the usual pattern after conditions settle |
| Persistent thirst, weight or appetite changes | Kidney, metabolic or hormonal disease | Book an examination promptly |
| Thirst with vomiting, weakness or marked lethargy | Potential serious systemic illness | Seek same-day care |
Important canine causes include diabetes mellitus, chronic kidney disease, Cushing's disease and effects of medicines such as corticosteroids or diuretics. An unspayed female dog with increased thirst and illness also needs assessment for pyometra.
In cats, kidney disease, diabetes and hyperthyroidism are particularly relevant. High calcium, liver disease and other disorders can affect either species. Diabetes insipidus is a different, uncommon disorder of water regulation; it should not be the first conclusion drawn from a thirsty animal.
How do vets investigate?
The history includes diet, medicines, reproductive status, weight and appetite. Urine concentration, glucose and other urine findings are interpreted alongside blood tests. Culture, imaging or specific hormone tests may follow depending on the results.
Veterinary guidance on investigating increased thirst explains why a combination of tests is usually needed. One dilute urine sample does not by itself establish kidney failure, and one result must be interpreted in its clinical context.
When is this an emergency?
Seek immediate care for unproductive urinary straining, collapse, severe weakness, repeated vomiting or breathing difficulty. A thirsty unspayed female that is lethargic, vomiting or has abdominal enlargement needs urgent examination even without vaginal discharge. A diabetic animal that becomes unwell also needs prompt assessment.
What to do now
- Do not restrict water. Increased drinking may be compensating for fluid losses.
- Measure what you offer over a full day if practical, accounting for other bowls, spills and wet food.
- Record toilet frequency, urine volume, appetite, weight and energy.
- Bring a complete medicine and supplement list to the vet.
- Ask whether a fresh urine sample is useful and how to collect and store it.
Water intake varies with food moisture, temperature and activity, so there is no single normal figure that diagnoses every dog or cat. A clear sustained change from the individual's baseline is useful information even without a perfect measurement.
Common mistakes
- Removing water overnight to prevent accidents.
- Assuming increased thirst is inevitable with ageing.
- Stopping prescribed steroids suddenly.
- Attempting a water-deprivation test at home.
Treatment and ongoing monitoring
Treatment targets the cause, and improvement may be partial or gradual depending on the disease. Keep the drinking and urination record after treatment starts, but do not adjust insulin, hormone medicines or fluids from thirst alone. Routine check-ups and attention to trends can help detect changes before severe illness develops.
Frequently Asked Questions
Can a thirsty animal still be dehydrated?
Yes. Drinking may not keep up with ongoing losses or illness.
Does this always mean diabetes?
No. Several kidney, hormonal and medication-related causes can produce the same signs.
Should I measure water for several days before booking?
Do not delay assessment of an unwell animal. Bring whatever observations you already have.
Will treatment return drinking to normal?
Sometimes, but chronic disease or necessary medication may leave an ongoing increase. Your vet will explain the expected pattern.
Increased thirst is a useful signal, not a diagnosis. Keep water available and use the change to guide a timely investigation.
Explore more practical guidance on recognising health changes at ASK A VET™.
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