Why do dogs eyes water?

As someone who spends a lot of time with dogs, I know a watery eye can grab an owner’s attention faster than a limp or a cough. You notice it after play, when grooming, or coming back from a windy walk; the fur below the eye stains, the face looks perpetually damp, and you worry the dog might be uncomfortable. For many owners the concern is partly cosmetic — tear stains on a white coat — and partly about comfort and sight. A little tearing that clears quickly with no other signs is usually not a major problem, but persistent watering, thick or colored discharge, or signs of pain may mean the dog’s day-to-day life and vision are being affected and deserve a vet visit.

Bottom-line summary: What watery eyes in dogs usually indicate

Most of the time a dog’s eyes water because something is irritating the eye surface, or because excess tears can’t drain normally. Common causes include simple irritation from dust or wind, allergic reactions, mild infections, or a blocked tear drainage system. Typical benign patterns are a short burst of tears after exposure to smoke or shampoo, or a chronic, clear overflow in breeds with shallow eye sockets. Red flags that should prompt contact with your veterinarian include persistent or worsening tearing, colored or sticky discharge, squinting or rubbing, sudden onset, or any sign that vision is affected.

Inside the dog’s eye: the biology of tearing and discharge

Tear production is a normal, protective process. Tears form a thin, multi-layered film over the eye that keeps the surface moist, washes away small particles, and supports clear vision. The film has three components: a watery layer that hydrates and carries oxygen, a thin oily layer that slows evaporation, and a mucous layer that helps the film stick to the eye. The watery layer comes from tear glands located near the eye; the oil layer is produced by small glands around the eyelid margin.

Tears are not meant to spill over the face. A drainage system — the puncta (tiny openings), small ducts, and a canal that empties into the nose — normally carries tears away. If production increases suddenly, or if drainage is reduced, tears reach the fur and make the area look wet. Reflex tearing is a short, often heavy production caused by an immediate irritant; chronic overproduction may be a response to ongoing surface irritation or poor drainage. I typically see reflex tearing after a blast of wind or when a dog gets shampoo in the face, whereas chronic overflow is more common in flat-faced breeds or dogs with long facial hair.

Common triggers — allergies, irritants, infections and more

External irritants are frequent culprits. Dust, airborne pollen, smoke, strong household cleaners, and even tearful human cologne can nick the eye surface and provoke tearing. Windy walks or rubbing against grass and branches may produce a sudden watery eye. Seasonal patterns may be present when environmental allergens — pollens, molds — are higher; dogs can suffer seasonal allergic conjunctivitis and water more in spring or fall.

Breed anatomy matters. Brachycephalic breeds (pugs, bulldogs, Shih Tzus) often have shallow or prominent eyes and may not blink fully, so the eye surface dries or gets irritated and produces more tears. Other breeds with long facial hair around the eyes or narrow eyelid openings may be prone to “epiphora,” a chronic overflow where tears stain the fur. Age and prior trauma can change the drainage anatomy; a past facial injury may have narrowed the ducts. Foreign bodies like small seeds or insect parts commonly provoke sudden, one-sided watering and a lot of blinking. Certain medications or systemic illnesses can also affect tear production, though that is a less common trigger.

Red flags: signs that deserve prompt veterinary attention

Watery eyes that are clearly watery and short-lived after a clear exposure are often low risk. But there are several signs that suggest a problem that needs veterinary attention. If discharge becomes colored (yellow, green, brown), thick, or sticky, that pattern is more likely linked to infection or secondary changes. Signs of pain — persistent squinting, holding the eye partially closed, pawing at the face, or avoidance of bright light — may suggest corneal damage or an ulcer, which can progress quickly if untreated.

Sudden vision changes, a dilated or irregular pupil, or swelling around the eye suggest deeper ocular or even neurological issues. Worsening symptoms over hours to days, both eyes involved when only one should be affected, or systemic signs such as fever, loss of appetite, or unusual lethargy are other reasons to seek prompt care. In short, if the dog seems uncomfortable, is rubbing the eye until it bleeds, or if you notice any change in behavior or mobility related to vision, don’t delay.

What to do first: immediate owner actions and when to call the vet

1. Observe and document. Note when the tearing started, whether it’s one eye or both, what the fluid looks like (clear, cloudy, colored), and any recent events — grooming, walks, new cleaners, medications, or signs of trauma. A short video of the dog blinking or rubbing the eye can be very useful for a vet.
2. Gently clean the area. Use a sterile saline solution or cooled boiled water (cooled to room temperature) and a soft, clean cloth or single-use gauze. With the dog calm and still, dab from the corner of the eye outward and change cloths to avoid moving material back toward the eye. Avoid using cotton swabs in the socket or applying any household ointments or human eye drops unless specifically advised by a veterinarian.
3. Remove obvious irritants and limit exposure. If you can see a hair or small object on the lashes, you may be able to gently lift it off with a clean fingertip or soft tweezers only if the dog stays still and you can do so without pressing on the eyeball. Otherwise, keep the dog from pawing the eye and seek veterinary removal.
4. Avoid home remedies and over-the-counter products that aren’t labeled for canine eyes. Some human drops can alter tear film balance or cause harm. If you have a vet-prescribed drop, follow the instructions exactly and keep a log of doses and any changes.
5. Call or visit your veterinarian when your notes show persistent tearing lasting more than 24–48 hours, any thick or colored discharge, signs of pain, sudden onset after an injury, or if you suspect a foreign body. Bring your observations and any photos/videos; these details speed diagnosis and help the clinician decide whether same-day attention or an urgent referral to an eye specialist is needed.

Home fixes and training: reduce triggers and prevent recurrence

Small changes at home can reduce trouble. Keep indoor air clean with regular vacuuming, reducing smoke exposure, and using an air filter if airborne particles are a known issue. Outside, choose walk times and routes that avoid heavy pollen, dusty fields, or strong winds. If your dog’s tearing is worse in a particular season, altering walk times to morning or evening may help reduce pollen exposure.

Grooming is often overlooked. Trim long hairs around the eyes carefully; I usually recommend blunt-ended scissors or a professional groomer who knows how to work near the eye. Clean fur that is chronically stained so it doesn’t trap debris or promote skin irritation. Training your dog to accept gentle face handling is also valuable: short, calm handling sessions with rewards can make future cleaning or vet exams less stressful. Reinforce calm behavior around the face and practice short tolerations to the touch near the eye before you actually need to clean it.

Handy gear: grooming tools, eye cleansers and vet-recommended supplies

Keep a small eye first-aid kit on hand: sterile saline solution sold for wound or eye care, soft microfiber cloths, single-use nonwoven gauze pads, and blunt-ended grooming scissors. Veterinarian-approved eye wipes designed for pets may be helpful for frequent cleaning of stained fur; choose products labeled for animals and avoid any with strong fragrances. An Elizabethan collar (cone) or inflatable alternative can prevent self-trauma if your dog is rubbing the eye persistently while you arrange veterinary care. For any medication — drops, ointments, or oral drugs — use only those prescribed by your veterinarian and store them according to instructions.

Practical tips you can use today

In my experience, owners who learn to observe patterns — when tearing appears, what it looks like, and what environmental factors link to flare-ups — can prevent a lot of unnecessary stress for their dogs and themselves. Simple, conservative measures often resolve non-urgent cases. But the eye is unforgiving: delays in treating ulcers or infections can lead to pain and permanent vision loss. When in doubt, document what you see, keep the eye clean with saline, and call your veterinarian. Quick, informed action preserves comfort and sight.

Sources and further reading

• Merck Veterinary Manual: “Epiphora (Excessive Tearing) in Dogs and Cats”
• American College of Veterinary Ophthalmologists (ACVO) Client Information: “Tear Stains and Excessive Tearing (Epiphora) in Dogs”
• American Veterinary Medical Association (AVMA): “Conjunctivitis and Eye Discharge in Dogs” client education
• Gelatt, K. N., Veterinary Ophthalmology, 6th Edition, Wiley-Blackwell — textbook overview of tear film, lacrimal anatomy, and diseases
• Cornell University College of Veterinary Medicine: Companion Animal Ophthalmology client resources on eye discharge and care