Though your dog may see the world as their water bowl, they’re not immune to waterborne parasites and pathogens. Here’s what you should look out for when spending time with your dog around bodies of water.

Giardia In Dogs
Giardia are single-celled parasites that infect dogs, cats, humans, and many other mammals. The parasite takes up residence in the small intestine of the host. It’s transmitted in the form of cysts that the host passes in their stool.
Once outside the body, the cysts are hardy, surviving for long periods of time in water and on surfaces. The cysts can wash into lakes and streams after a rainfall and can also be found in communal water bowls at dog parks. The cysts are found in both stagnant and fast-moving bodies of water.
Dogs with giardiasis may develop greasy, foul-smelling diarrhea, vomiting, and weight loss. Thankfully, the infection is treatable and generally does not cause serious complications. Healthy adult dogs are often asymptomatic carriers. Puppies and senior dogs are vulnerable to severe dehydration if the diarrhea is not treated.

Leptospirosis
Leptospirosis is an infection caused by leptospira bacteria. An infected animal sheds the bacteria through their urine, and it can survive for a long time in water or soil. Your dog is more likely to encounter the bacteria in stagnant and slow-moving water.
Dogs with leptospirosis may have anything from no symptoms at all, to life-threatening kidney failure, liver failure, lung disease, and internal bleeding. Symptoms include fever, lethargy, shivering, and changes in the amount and frequency of urination.
Leptospirosis can be prevented by keeping your dog from swimming in or drinking stagnant water, especially from puddles, lakes, marshes, and ponds. You can also ask your veterinarian if the annual leptospirosis vaccine is right for your dog.

Blue-Green Algae
Blue-green algae itself is not harmful to dogs, but some algae produces toxins that can be lethal. Unfortunately, it’s impossible to tell just by looking if algae is harmful. It’s best to keep your dog away from any murky or unclean water. Stick to bodies of water that are known to be safe for swimming. If your dog is exposed to potentially toxic water, they may ingest it when they lick themselves.
Blue-green algae intoxication causes vomiting, diarrhea, seizures, disorientation, and excessive drooling in as little as 15 minutes. It can be fatal even with treatment, so it’s imperative that you take your dog to the vet or emergency vet clinic immediately if you notice any symptoms.

Can My Dog Drink From The Ocean?
While smelly, salty ocean water may not seem appetizing to us, some dogs can’t resist lapping it up. Dogs can also take in salt water while playing fetch with absorbent toys like tennis balls. After drinking small amounts of salt water, your dog may experience vomiting and diarrhea. If your dog drinks an excessive amount of salt water, it can cause severe dehydration, which leads to brain swelling and seizures. Saltwater poisoning can be lethal, so if you suspect your dog has swallowed too much, seek emergency veterinary treatment.

Protecting Your Dog From Waterborne Illnesses
Though the bacteria and parasites that lurk in water come with risks, you can still safely enjoy playing by lakes, shores, and streams with your dog.
If your dog likes to swim, always take them to clean bodies of water that are known to be safe for swimming. Take your dog to the vet annually for an exam and fecal test to check for parasites, and ask your vet if they recommend the leptospirosis vaccine for your dog.
When it comes to safe drinking water for your dog, tap, spring, or filtered will do. If the water is safe enough for you, it’s usually safe for your dog to drink. Always bring your dog fresh water and a portable bowl when you’ll be spending time in or around bodies of water, and encourage them to take breaks to drink.