How Much Water Should a Dog Drink a Day? Chart by Weight

How much water should a dog drink a day? For a healthy adult dog, the usual veterinary figure is about 50–60 milliliters per kilogram of body weight, including the water in food. In US units that’s a little under an ounce per pound. Most owners never need to measure it, but knowing the normal range helps you notice when something changes, and a big change in thirst can be an early sign of several common illnesses.

Below you’ll find a chart by weight, a worked example using our dog water intake calculator, what changes a dog’s thirst, and the point at which drinking a lot becomes a reason to call your vet.

How much water does a dog need per day?

Healthy dogs generally drink between 50 and 60 mL of water per kg of body weight each day. The exact amount depends on the moisture in their food, the temperature and humidity, and how active they are. The Merck Veterinary Manual gives a similar general range for mammals in a comfortable environment, about 44–66 mL per kg.

To convert that to US units:

• 50 mL per kg is about 0.77 fl oz per pound
• 60 mL per kg is about 0.92 fl oz per pound

So “about an ounce per pound” is a handy upper-end rule of thumb, as long as you remember it’s a rough guide and not a target your dog has to hit.

Dog water intake chart by weight

This chart uses the same formula as our calculator (50–60 mL per kg per day). The last column is the level vets use to define excessive drinking: more than 100 mL per kg per day.

Dog’s weight	Normal daily water	In cups	Too much (over)
10 lb (4.5 kg)	7.7–9.2 fl oz	about 1 cup	15 fl oz
20 lb (9.1 kg)	15–18 fl oz	about 2–2¼ cups	31 fl oz
30 lb (13.6 kg)	23–28 fl oz	about 2⅞–3½ cups	46 fl oz
50 lb (22.7 kg)	38–46 fl oz	about 4¾–5¾ cups	77 fl oz
70 lb (31.8 kg)	54–64 fl oz	about 6¾–8 cups	107 fl oz
90 lb (40.8 kg)	69–83 fl oz	about 8⅝–10⅜ cups	138 fl oz

These amounts include water from food. A dog on canned food gets a good share of its water from the bowl of food, not the water bowl.

Worked example: a 50 lb dog

Here’s how our water intake calculator handles a 50 lb dog, step by step:

1. Convert to kilograms. 50 lb × 0.4536 = 22.7 kg.
2. Low end. 22.7 kg × 50 mL = about 1,134 mL a day.
3. High end. 22.7 kg × 60 mL = about 1,361 mL a day.
4. In US units. That’s roughly 38–46 fl oz, or about 4¾–5¾ cups.
5. Warning level. 22.7 kg × 100 mL = about 2,268 mL, or roughly 77 fl oz (about 9½ cups). If your dog is regularly drinking more than this, it’s worth a vet visit.

If the same dog eats a lot of canned food, the water bowl might only go down by half of that and the dog is still perfectly hydrated.

What changes how much water a dog drinks?

Water intake naturally moves around from day to day. The main reasons:

• Food type. Canned food is 60% to more than 87% water. Dry kibble is only 3–11%, and semi-moist food is 25–35%. Dogs on dry food drink more from the bowl.
• Heat and humidity. Dogs cool themselves mainly by panting, which uses water.
• Exercise. A long hike or a game of fetch means a bigger drink afterwards.
• Salty food. A high-salt diet is one of the listed causes of increased drinking. Salty table scraps count.
• Medicines. Steroids such as prednisone, the diuretic furosemide and the seizure drug phenobarbital can all make dogs drink and urinate more. If your dog has just started a new medicine and is suddenly thirsty, mention it to your vet, but don’t stop the medicine on your own.

How do I measure my dog’s water intake at home?

You only need to do this if you’ve noticed a change, or your vet asks.

1. Pick one bowl and remove other water sources for the test (if you have several pets, this is harder; your vet may suggest another approach).
2. Fill the bowl with a measured amount, for example 2 liters (about 8½ cups).
3. Measure what’s left at the same time the next day, and add any refills you gave.
4. Repeat for a few days and average the results, because intake varies day to day.
5. Divide the daily total in mL by your dog’s weight in kg. Above about 100 mL per kg suggests excessive drinking.

Our dog water intake calculator does the math and shows the warning level for your dog’s weight.

When is drinking too much water a problem?

Vets define excessive thirst (polydipsia) in dogs as drinking more than about 100 mL per kg per day. That figure is a guide, not a hard line: a dog that normally drinks very little can have a real problem at a lower amount, which is why a change from your dog’s usual habit matters as much as the number.

Common causes of drinking and urinating more include:

• diabetes mellitus
• kidney disease
• Cushing’s disease (hyperadrenocorticism)
• liver disease
• a womb infection called pyometra in unspayed females
• high blood calcium
• some medicines, as listed above

Many of these are very treatable, especially when caught early. Your vet will usually start with a urine test and blood tests. Don’t cut back your dog’s water to “fix” the thirst. That can cause dangerous dehydration.

What about dogs that don’t drink enough?

Some dogs drink little from the bowl because they eat wet food, and that’s fine. But a dog that suddenly stops drinking, can’t keep water down, or has vomiting or diarrhea can become dehydrated. Call your vet the same day.

Hot weather is the big risk. Heat stroke is an emergency. Signs include fast breathing, dry or sticky gums, gums of an abnormal color, lethargy, confusion and seizures. Flat-faced breeds such as pugs, boxers and bulldogs can overheat even when it’s only moderately warm. Always leave shade and fresh water, and never leave a dog in a parked car.

Simple ways to keep your dog well hydrated

• Keep fresh, clean water available at all times, and wash the bowl daily.
• Put a second bowl in another room or outside. The Merck Veterinary Manual notes that multiple water sources encourage drinking.
• Take water on walks and hikes, especially in summer.
• If your dog is fussy about drinking, adding some wet food or water to meals raises total intake.
• If your dog is overweight, remember that treats and table scraps (often salty) add up. See how many treats a dog can have and our post on how fast a dog should lose weight.

When to call your vet

• Your dog is drinking noticeably more than usual for more than a couple of days, or needs the bowl refilled much more often.
• Measured intake is regularly above about 100 mL per kg per day.
• Your dog is also urinating more, having accidents indoors, losing weight, eating more or less than usual, or vomiting.
• Your dog stops drinking, or shows signs of heat stroke (go to a vet or emergency clinic straight away).

For how much to feed alongside all this water, see our guide on how much to feed a dog.