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Why is my dog so thirsty at night?

You’re sleeping pretty well until, again, you hear it — lap, lap, lap…lap, lap, lap. Your dog is at his water bowl yet again. You think to yourself that you should really be used to it by now, that the sound should aggravate you a little less. You are just left trying to get back to sleep while pondering — Why is my dog so thirsty at night, and what should I do about it?

Why is my dog so thirsty at night?

Sometimes, you’ll notice your dog is a little more thirsty than usual after a couple of fast-paced, long, hot days, and that is fine. Things become problematic only when he remains thirsty night after night. It is a possibility that your dog may have a serious medical condition, so you probably want to consult a vet for an exam and a professional opinion. The following is a list of medical problems dogs can have that would make them unusually thirsty.


Polydipsia is the medical term for a condition where your dog suffers from excessive thirst. It, however, is not necessarily a physical condition but probably a form of subconscious behavioral issue, and the reasons behind it are argued by professionals.

Scarcity Mindset

Who knows what the circumstances may have been, but your dog was left without water for a period of time, and maybe he was rescued from his abusers by the Humane Society. Great, he’s been saved, but now, he’s suffering from a “scarcity mindset,” in which he is afraid that water will be withheld from him again, so he is drinking all he can, subconsciously.

Lack of Attention

Your dog may be bored, and drinking is a way to help him pass the time. It doesn’t make much sense, but neither do many of the things we, as humans do. When he drinks, do you ever tell him how adorable he is or scratch his coat for a split second? Maybe he feels pouty like he needs some attention. Subconsciously, his mind might say that drinking will get him some.

Urinary Tract Infection

Most times, urinary tract infections or UTIs usually present as bacterial infections but can be fungal infections. UTIs occur more often than any other infectious disease affecting dogs.

Though a few dogs won’t show any symptoms, the ones that do will present with bloody or cloudy urine with a strong odor. They may show lethargy or a change in appetite. They can vomit or contract a fever. They may strain or whimper during urination.  They often lick the area in and around the urinary opening, and They may require potty breaks more frequently and could urinate in the house. It isn’t uncommon for them to suffer weight loss or severe back pain.

Diabetes Mellitus

When your dog has diabetes, their glucose to insulin setup isn’t functioning properly. There are two forms of diabetes, as follows.


In insulin-deficient diabetes, not enough insulin is produced by the dog’s body, because of a damaged or otherwise malfunctioning pancreas. These dogs must have shots of insulin each day as a replacement for the insulin their body is supposed to produce. In canines, this is the type found most often.


In insulin-resistant diabetes, some insulin is produced, but it isn’t utilized as it should be in the dog’s body. The cells don’t react to the insulin’s action. Therefore, glucose never makes it out of the blood to make it into the cells.

Kidney Disease

Kidney disease is an umbrella term encompassing a number of conditions affecting the kidneys. With kidney disease, you usually see a gradual decline, eventually reaching renal insufficiency. Some other symptoms of kidney disease are lethargy, frequent urination, and poor appetite.

Cushing’s Syndrome

Hyperadrenocorticism, better known as Cushing’s disease or Cushing’s syndrome. It is caused most often by a tumor located in the pituitary gland. Cushing’s syndrome is actually quite common, but it’s under-diagnosed because the testing is complex and the treatment is ongoing and extremely expensive. There must be constant monitoring. If you’ve heard of Cortisol, a dog with Cushing’s syndrome overproduces this chemical. Some other symptoms are frequent urination, weakness, loss of muscle, lesions on the skin, thinning skin, obesity, lethargy, and hair loss on the neck, flanks, and perineum.

Liver Disease

When a dog’s liver isn’t working, it can be mortal. Not only does it aid with digestion, but it helps with blood clotting, and most importantly, it removes toxins from his body. Take heart, though, oftentimes, liver disease can be treated. Some other symptoms to look for are loss of appetite, diarrhea, vomiting, weight loss, unsteadiness, frequent urination, jaundice, confusion, weakness, blood in urine or feces, ascites (fluid buildup in the stomach), or seizures. This is a disease that needs to be detected early on, because if not, hepatic encephalopathy, a very serious brain condition, can occur.


About 10.8% of dogs get cancer each year in the United States. Some of those cancers are quite treatable, and others are aggressive and untreatable at this time. Much cancer treatment research goes on each year to find a cure for these cancers. Only your vet can diagnose cancer, and the signs are different for different types. You can read more about cancer in dogs on the AVMA website. Some common things to look for, though, are lumps, odd-smelling breath, discharge, swelling, wounds or sores that don’t heal, sudden weight loss, or lethargy. Each cancer is different, so if you suspect that your dog has cancer, don’t waste any time getting him to the vet for evaluation.

Heatstroke (Hyperthermia)

Heatstroke is non-fever hyperthermia, where the temperature can soar above 106 degrees Fahrenheit. This happens when the mechanisms in a dog’s body that dissipate heat cannot keep up with the extremely high external heat. This type of hyperthermia can cause multiple organ dysfunction. Heatstroke happens most often to long-haired breeds and brachycephalic breeds. Also, it is more common in young dogs than in old dogs. Some other symptoms include panting, dehydration, excessive drooling, fever above 103 degrees Fahrenheit, little or no urine output, rapid heart rate, irregular heartbeat, cardiopulmonary arrest, vomiting blood, blood in stool, confusion, seizures, muscle tremors, wobbly (drunken) gait, or unconsciousness.

Diabetes Insipidus

Caused by a hormonal abnormality, when a dog’s body is unable to control how it processes fluids, diabetes insipidus occurs. It is a salt and water metabolism disorder. Diabetes insipidus is extremely rare. Some other symptoms include heavy urination, fatigue, dehydration, or weight loss.


Hyperthyroidism occurs when the thyroid hormone is overproduced by a dog’s body. His metabolism speeds up resulting in potential weight loss, diarrhea, anxiety, and a myriad of other symptoms.


Parasites, like the internal heartworm, the intestinal ringworm, and the external tick are nightmares to dogs. Ticks are just gross to begin with. You can see them grow, turn gray with blood, and just eeewww! Ringworms and heartworms, you cannot so readily detect, though. They can be present for a while before you notice them. They can eventually cause serious illness. There are also hookworms, roundworms, tapeworms, whipworms, coccidia, giardia, spirochetes, fleas, lice, mites, and more. For more information on parasites and the symptoms of parasites, see the AKC website.

Should dogs drink water during the night?

An average adult dog weighing 10 pounds would need to drink roughly 10 ounces of water per day. It sure doesn’t sound like much, does it? Well, 10-pound dogs are pretty small, too. A 20-pound dog would need to drink a 20-ounce bottle’s worth of water per day. The rule, obviously, is one ounce of water per pound of body weight per day, unless there are other factors to consider. For instance, those figures are for mostly sedentary dogs. Other circumstances must always be considered when deciding how much water to allow your dog. If your dog is uber-active, he will require more water than his sedentary counterparts. Puppies dehydrate more quickly than fully-grown dogs, so they may need more water. You must be the judge, based on your dog’s body type, weight, age, condition, and activities. You know him better than anyone. Healthy dogs will only drink as much water as they require.

Why is my dog suddenly drinking a lot at night?

Yes, your dog is drinking tons of water at night, but he didn’t always do that. If your dog didn’t always drink a lot but is suddenly very thirsty at night, that doesn’t mean he has one of the serious health problems listed above. It could be something as simple as exertion, vomiting, diarrhea, fever, dehydration, infection, or medications, but it could also be something serious like poisoning, so if your dog has serious symptoms, like pale or yellow gums, heart racing, coughing up or vomiting blood, or collapsing, get him to the vet as fast as you can.

What to do about my dog being so thirsty at night?

If your dog is obviously drinking much more water than normal, it’s time for you to make him an appointment with the vet. Do not waste any time, because while it may be something quite simple, he could be plagued with a very serious condition that would require a vet’s expertise to both diagnose and treat. Listen to what your vet has to say, and follow his instructions.

When you arrive at the vet, you should probably have with you a copy of your dog’s vaccination records and any medical records. You should ponder and be prepared with any information you think may be helpful to the vet. Has he been around other dogs for the first time? Did you just take him out of state? Have there been changes in his diet, eating habits, or weight? Also, ponder what questions you may want to ask.

Your vet will examine your dog. He will most likely order some lab work, like a complete blood count and a urinalysis. Other testing will probably be run, as well. This is all to gauge how your dog’s kidneys and liver are functioning, which will help him narrow down the cause of your dog’s excessive thirst. If the first testing is not conclusive, your vet may need to investigate further.

Why is my senior dog drinking so much water?

Older dogs can drink a lot because they suffer from an infection, like a UTI, which is very common in senior dogs, or they can suffer from other simple ailments, such as dehydration, exertion, or a reaction to a medication, but it could also be something more serious. Senior dogs also quite often suffer from kidney disease, diabetes mellitus, bladder stones, bladder tumors, and bladder polyps. If your senior dog is obese, he can be especially prone to insulin-resistant diabetes.

Should I withhold water from my dog at night?

This simple answer to this question is a big, huge — NO! Withholding water from your dog is not a good idea. In fact, it is a bad idea and dangerous for more than one reason. 

Scarcity Mindset

When you limit a dog’s drinking water, you condition him to drink all his water when you do put it out. Dogs many times, from that point on, drink obsessively all the time. Anytime they have access to water, they consume all they can.


Dehydration can occur when water is withheld. This leads to UTIs, which are extremely painful and can cause bladder stones, eventually leading to permanent kidney damage, and even sepsis. It isn’t worth it just to not have to get up and let him out once at night.