How Much Water Should a Dog or Cat Drink Daily?

Water is easy to overlook until something is obviously wrong. But changes in how much your pet drinks are often one of the earliest signs that something is off — and one of the most reliable health signals you can track at home.

The Basic Guideline

Dogs: roughly 50–60 ml per kilogram of body weight per day under normal conditions. A 10 kg dog should drink approximately 500–600 ml daily. Active dogs, lactating dogs, and dogs in hot weather will drink more.

Cats: roughly 40–60 ml per kilogram per day. A 4 kg cat needs approximately 160–240 ml. Cats on wet food get a significant portion of their water from food, so their bowl intake will look lower than for cats on dry food.

These are starting-point figures, not exact targets. The key is knowing your individual animal's normal.

Why Hydration Matters More for Cats

Cats have a low thirst drive compared to dogs — an evolutionary trait from desert-dwelling ancestors who got most of their moisture from prey. A cat eating exclusively dry kibble is often in a mild state of chronic dehydration, which over time contributes to kidney disease and urinary problems (both very common in older cats).

If your cat is on dry food, adding wet food to the diet or a cat water fountain (cats prefer moving water) can make a real difference.

Signs Your Pet Is Drinking Too Little

Dry, sticky gums
Skin that does not spring back quickly when gently pinched (the scruff test)
Lethargy or reduced energy
Dark yellow urine or urinating less frequently than usual
Sunken eyes (more visible in cats)
Loss of appetite

Mild dehydration in a hot day or after exercise is normal. Persistent signs warrant a vet visit.

Signs Your Pet Is Drinking Too Much

Increased thirst (polydipsia) paired with increased urination (polyuria) is one of the most important symptom pairs in veterinary medicine. The combination — often called PU/PD — is associated with:

Diabetes mellitus (dogs and cats)
Kidney disease (especially in cats over 10)
Cushing's disease (dogs, less commonly cats)
Hyperthyroidism (cats)
Liver disease
Urinary tract infection
Certain medications (steroids in particular)

If your pet is suddenly drinking noticeably more than usual for more than a couple of days, book a vet appointment. A simple blood and urine test can rule out the most common causes quickly.

How to Track It

You do not need to measure water to the millilitre. What you need is a sense of what normal looks like for your pet.

A few practical approaches:

Use a bowl of consistent size. If you refill it once a day normally and suddenly you are refilling it twice, you will notice.
Note water intake in a daily log alongside food intake, walks, and behaviour — changes become visible over days or weeks rather than being easy to dismiss.
After a vet visit where bloodwork shows early kidney changes, your vet may ask you to monitor intake more carefully. A written record makes that straightforward.

Water Quality and Bowl Type

Wash water bowls daily. Bacteria build up quickly, especially in plastic bowls (which also harbour micro-scratches where bacteria hide). Stainless steel or ceramic is preferable.
Some pets dislike the taste of heavily chlorinated tap water. If your pet seems reluctant to drink, try filtered water or let tap water sit for a few hours before filling the bowl.
Water fountains work well for cats and some small dogs — the movement encourages drinking.
Place water away from the food bowl. Cats in particular often prefer their water source to be separate from where they eat — possibly an instinct related to not contaminating a water source near prey.

During Hot Weather and After Exercise

Dogs lose water through panting. On hot days and after walks, offer water more frequently and in larger amounts. Check that outdoor water bowls are in shade. On very hot days, ice cubes in the bowl can help.

Never restrict water access unless specifically instructed by your vet for a medical reason.