Unlike cats, who regularly fail to drink enough water, most dogs readily drink enough water to remain healthy. However, some dogs occasionally try to drink excessive amounts of water, which can signal the presence of several different health problems.
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Common Causes of Excessive Thirst in Dogs
Although there are a variety of different reasons your dog won’t stop drinking, the following nine are among the most common. No matter why you believe your dog is drinking large quantities of water, it is important to consult with your vet, to ensure a proper diagnosis is made and a treatment plan devised.
The simplest reason dogs drink large quantities of water is that they are dehydrated. Your dog may, for example, drain an entire bowl of water following a summertime walk or following an extended session of fetch.
While it is still a good idea to consult your vet anytime you suspect that your dog is dehydrated, most dogs will recover from mild cases of dehydration by simply drinking a bunch of water and resting in a cool location for a while.
2. Behavioral Issues
Anxious and nervous dogs occasionally exhibit repetitive or compulsive behaviors including excessive water consumption – a condition sometimes called psychogenic thirst.
While most healthy dogs are unlikely to become ill from drinking reasonable quantities of water (they’ll just have to go outside to relieve themselves more often), it is still important to discuss the issue with your vet. Treating these types of problems will require that you address the underlying reason your dog is suffering from anxiety.
3. Dietary Problems
Some dogs begin drinking large quantities of water following a change in food. Some commercial kibbles, for example, have very little water content, which will spur your dog to make up for this by drinking more.
Human foods – especially those high in salt – can also cause dogs to drink more water than normal.
Excessive thirst frequently occurs following the administration of several medications, including corticosteroids and diuretics. These types of medications will often spur your dog to drink huge quantities of water and require more trips outside than usual.
Contact your vet if you notice that your dog has begun drinking large amounts of water following the administration of a new medication or a change in dosage.
5. Urinary Tract Infections
Dogs can suffer from urinary tract infections (UTIs) when pathogenic bacteria are able to colonize the urethra or bladder. Dogs suffering from UTIs may urinate more than normal and experience pain while urinating; many will even pass significant amounts of blood in their urine.
Excessive water consumption often follows these symptoms, and likely serves as an evolutionary adaptation for flushing the offending bacteria from the bladder and urethra. UTIs are very common in dogs (particularly females), and they are usually easy to treat with a course of antibiotics.
6. Kidney Disease
Your dog’s kidneys are responsible for two primary processes: filtering wastes and toxins from the bloodstream and regulating the amount of water in the body. This means that when a dog’s kidneys become damaged or diseased, it can affect the amount of water they drink.
Kidney disease is a serious medical condition that can precipitate from a number of causes, including high blood pressure, diabetes and infection, but it is often treatable with medications.
7. Cushing’s Disease
Cushing’s Disease is a disorder caused by the abnormally high production of hormones – primarily cortisol. In addition to excessive thirst, water consumption and urination, this disease can also cause dry skin, frequent panting, increased appetite, muscle weakness and nervous system problems.
Cushing disease is most commonly caused by tumors growing on the adrenal glands, so treatment either entails medications to repress the tumor’s activity or surgery to remove the tumor entirely.
Diabetes is one of the most common diseases to cause increased thirst and water consumption. Canine diabetes is generally the result of a dog’s inability to produce enough insulin for proper bodily function and glucose metabolism. This leads to high blood glucose levels, which causes problems ranging from blurry vision to poor nerve function.
The excessive water consumption that accompanies diabetes is the body’s way of trying to flush this excess glucose from the blood. Diabetes cannot be cured, but it can be managed with medications.
9. Liver Disease
Along with anorexia, seizures and unexplained weight loss, excessive thirst is often caused by liver disease. Liver disease can be caused by a variety of different conditions, including everything from heartworms to the ingestion of some plants or fungi.
Proper treatment requires that you seek immediate veterinary attention so that a proper diagnosis can be made. Many types of liver disease and dysfunction are treatable, but prompt action is imperative for the best chances of success.
Defining Excessive Thirst: How Much Is Too Much?
Healthy dogs typically consume about 100 milliliters of water per kilogram (approximately 1.5 ounces per pound) of body weight per day. In other words, a 50-kilogram (110-pound) dog would require 5 liters (approximately 170 ounces) of water per day.
To determine how much water your dog consumes in a 24-hour period, you’ll simply need to measure the amount of water provided at the beginning of the trial, and then subtract the remaining portion from this total at the end of the 24-hour period.
Note that some dogs consume water from places other than their water dish, including open toilets, puddles and dripping faucets. Accordingly, you’ll need to eliminate these sources when evaluating your dog’s drinking behavior.
Excessive water consumption in your dog is often a result of minor problems, such as dehydration, but because it can also signal the presence of much more serious conditions, a trip to the vet is always appropriate. Don’t procrastinate, as this can allow some problems to worsen, making treatment more difficult.
Dr. Lillian is a D.V.M. passionate about promoting awareness of dogs. She shares her expertise through her blogs on canineweekly.com and provides animal care services, including internal medicine, dermatology, and emergency care. Dr. Lillian is committed to contributing to animal welfare.