28/06/2025
WATER POISONING IN DOGS – BE AWARE OF THE DANGERS
As the weather gets hotter for many of us, the temptation is to take our dogs to streams, rivers, lakes or the beach for them to cool off, or give them their own paddling pools. In doing so, however it is worth being aware of a serious danger to them that may go unappreciated, or less recognized by owners, before the damage is done – and that is water poisoning. Or hyponatraemia, where a dog simply ingests too much water while swimming, playing or retrieving toys.
A smaller amount of water swallowed – fresh or sea water – may do them little harm, but excess amounts ingested can have far more devastating consequences.
FRESH WATER
There are two types of water poisoning to watch out for. The first is from fresh water – i.e. rivers, streams, paddling or swimming pools, or even hoses and sprinklers. Collies can be particularly obsessive about water, too, and may gulp down far too much of it in games where they may deliberately try to make water splash and then bite and swallow it.
The excess water intake then depletes sodium levels in the dog’s body, leading to the condition of hyponatraemia (water toxicity), which can wreak terrible damage to all organs in the body, including the brain.
Symptoms can include lethargy, bloating, vomiting, loss of coordination, drooling, pale gums and diluted pupils/glazed eyes. As the pressure in the brain increases, and its cells begin to die off, the dog may then have difficulty breathing, develop seizures, or slip into a coma. Untreated it can be fatal, but sometimes even after treatment, the damage done by the condition can be irreversible.
In hotter weather, you should also be mindful of more toxic algae blooms in fresh water lakes, ponds or rivers that can be harmful to your dog. Often alerts will be put up about these in the form of signs or local social media posts, but if you have any doubts about their presence in water, it is best to avoid the water concerned.
SALT WATER
Drinking too much salt water from the sea can bring about a reverse problem of far too MUCH sodium entering your dog’s body. This can lead to similar symptoms to fresh water poisoning like vomiting and diarrhoea but eventually more serious dehydration leading to brain damage and seizures.
WHAT TO DO
If you see the beginning of any of the previously mentioned symptoms appear in your dog after a lengthier spell of drinking or playing in water, get them to a vet immediately, making sure you tell them you think water poisoning could be a possibility, and to urgently check their sodium levels to save valuable time.
Prevention, however, is always better than cure. So do be mindful of the risks of letting your dog ingest too much water, fresh or salt, anywhere. Particularly in one longer period. Also use proper floating and flatter retrieve toys – as in the illustration here - with a rope or canvas ‘tail’ that are easier for your dog to grab and close their mouth round in water, whereas rounder balls bob around too much, and your dog is likely to swallow far more water getting them.
As ever, commonsense is the key. Let your dog enjoy their watery fun and pleasures, while always being mindful of how much water they may be swallowing in the process – as some dogs will definitely swallow far more than others.
Do not leave dogs unattended in paddling pools if they persistently try to disturb and then bite and swallow the water. And do not let them do this for more than a minute or so at a time, if they appear to be swallowing a lot of it. The same is true with garden sprinklers.
Also limit how much time your dog spends retrieving toys out of sea water, and make sure you also have plenty of fresh water on hand for them to drink afterwards.
Life is always a balance between pleasures and risks. But in this case it definitely IS better to be safe than sorry. And I have just known so many otherwise wonderful family summer outings with dogs end tragically because no one realised the danger their dog faced in swallowing too much water.
All text © Carol Price 2025
SYMPTOMS OF WATER POISONING
Water intoxication can cause dogs to feel very poorly very quickly, so it’s important that owners can spot when something is wrong. The signs or changes in behaviors you should look out for in your dog (after they’ve been spending time in the water) include:
Staggering or loss of coordination
Tiredness
Weakness
Bloating
Vomiting
Passing large amounts of clear urine
Dilated pupils or glazed eyes
Excessive salivation (drooling)
In severe cases of water intoxication, a dog may have difficulty breathing, collapse, have a seizure, or fall into a coma.
When should I call my vet?
Contact your vet immediately if your dog shows any signs of water intoxication.
Your vet will want to carry out blood tests to measure your dog’s electrolyte levels. If your dog’s electrolyte levels are low and water intoxication is suspected, they will need fluids to pump electrolytes slowly back into their system. A treatment plan for water intoxication may include a diuretic (a type of medication that helps your dog p*e more).
If treatment is started quickly and symptoms aren’t severe, most dogs recover from water intoxication. However, if a dog’s symptoms are severe or neurological (affecting the brain), unfortunately, water intoxication can be fatal. This is because it can be extremely difficult to rebalance their sodium levels safely.
The size of the dog and the volume of water they have swallowed will determine if they have swallowed too much.
SYMPTOMS OF SALT WATER POISONING IN DOGS
Excessive thirst and urination: The body attempts to dilute the excess salt, leading to increased fluid intake and output.
Gastrointestinal issues: Vomiting and diarrhea are common, sometimes accompanied by drooling.
Lethargy and weakness: The dog may become unusually tired, weak, or disoriented.
Neurological signs: In severe cases, dogs may experience muscle tremors, seizures, confusion, or even coma.
What to do if your dog drinks salt water:
Provide fresh water: Encourage your dog to drink fresh water to help dilute the salt concentration in their system.
Monitor symptoms: Watch for any signs of distress and contact your veterinarian if symptoms worsen.
Limit further exposure: Prevent your dog from drinking more salt water and avoid excessive play in the ocean.
Seek veterinary care: If you suspect salt poisoning, especially with severe symptoms like tremors or seizures, seek immediate veterinary attention.
SYMPTOMS OF TOXIC ALGAE POISONING
Symptoms of toxic algae poisoning in dogs can vary depending on the toxin involved, but may include:
Vomiting
Diarrhea (sometimes bloody or dark)
Weakness or collapse
Excessive drooling
Stumbling or tremors
Seizures
Difficulty breathing
Paralysis
Jaundice (yellowing of the skin and gums)
Liver failure
What should you do if you suspect your dog has ingested toxic algae?
Seek immediate veterinary care: Time is critical in these cases.
DO NOT INDUCE VOMITING: This can be dangerous, especially if the dog is already showing neurological symptoms.
Rinse your dog with clean water: If you can, rinse any algae off their fur with clean water.
Report the incident: If you suspect a toxic algae bloom, report it to your local environmental agency.
