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Can Dogs Drink From Streams, Rivers, And Lakes On Hikes?

Gatsby dog standing in water

We love seeing our dogs happy, and watching them jump around and play in rivers and streams is pure bliss. But what about when your pup takes a sip from that creek or a big gulp from that lake?

Can dogs drink from streams, lakes, and rivers without getting sick? We’ll tackle this question with science-backed evidence so you can ensure your canine companion is safe and healthy on your next hike!

On a side note, I am not a veterinarian, pathologist, or biologist. If you are concerned about your pup drinking from outdoor sources, always discuss it and any symptoms with your vet. This article is meant to be a guide and should not replace information given to you by your veterinarian.

This post includes affiliate links but rest assured that we only recommend items we would use ourselves. And if you choose to make a purchase, we receive a small commission. No sponsorships, just the truth about our favorite finds.

💦What’s Hiding In The Water?

Gatsby dog standing in water. Can dogs drink from streams?

Many dogs love the water, and it seems harmless enough. People swim in lakes and rivers, so it must be okay for dogs, right?

An article from the European Journal of Development Studies looked at the water given to pet dogs in Brazil. Of the water given, 65% was considered not recommended for drinking. Even the pets given the same drinking water as the family had a whopping 38.5% that was not recommended for drinking.

This shows that even water perceived as safe is not always okay for dogs (and even people!) to drink. Let’s check out what’s lurking in untreated water. After that, we’ll discuss specifics to answer the question, ‘Can dogs drink from streams, rivers, and lakes?’

Harmful Algal Blooms (HABs)

HABs are more often found in coastal and marine areas but can be found anywhere in the United States. The most common organisms that cause HABs are cyanobacteria, sometimes referred to as blue-green algae.

Now, not all cyanobacteria are harmful. These little microscopic organisms are present in many aquatic ecosystems. However, certain types release toxins that harm pets, people, and wildlife.

The toxic effect of HABs occurs when the algae undergoes rapid growth due to high nutrient content in the water, particularly nitrogen and phosphorous. This can be caused by several things, such as agricultural runoff, pollution, sewage, and even your dog’s poop. You can read more about why you should pick up your dog’s poop here.

HABs are more often found in slow-moving or stagnant water in warm climates. They do not have a single identifying characteristic, so if you spot anything resembling algae on or below the water’s surface, do not let your dog wade, play, or drink from it.


Unlike HABs, leptospirosis is a bacteria. It is usually found in warm climates with high rainfall. It can be found in lakes, streams, rivers, and in the infected urine of other animals, especially farm animals.

Oklahoma State University tells us that over 200 strains of lepto can be found worldwide.

You’ll most likely find lepto bacteria in slow-moving or stagnant water, wet grass in the shade, and along the banks of lakes and rivers. You probably won’t see symptoms in your dog until after you’ve taken them home, as this bacteria can take a few hours to a few days to cause noticeable symptoms like diarrhea.

Pythiosis (rare)

Pythiosis is a water-borne parasite usually found only in tropical and subtropical climates. It may also occur in northern coastal regions after a tropical storm or hurricane. The highest risk for pythiosis is in the states bordering the Gulf of Mexico.

It is very rare for dogs to contract pythiosis, but this is one of the more severe diseases that dogs can contract from drinking outdoor water sources. Dogs with open wounds are at a higher risk, as are dogs who retrieve sticks underwater and then chew on them.

Dogs are more likely to encounter pythiosis in wetlands, swamps, and ponds than in streams and rivers.


Heartworms are not necessarily contracted from drinking outdoor water sources but are transmitted by mosquitoes that typically hang around stagnant water.

Heartworm is a parasite which is easily prevented with heartworm medication. However, if the parasite is allowed to infect the dog for long periods, it can cause serious problems in the heart and lungs.

Places with the highest risk of heartworm include the Southeast, especially in the Mississippi River Valley.


Like heartworm, Giardia is a parasite that can infect your dog. Dogs typically come in contact with Giardia if they drink from feces-contaminated water.

Giardia can be difficult to completely eliminate because dogs can easily reinfect themselves. The parasite forms a protective shell that can remain on their fur or in the environment for a long time. When the dog grooms itself, it can easily reingest the parasite, starting the cycle over.

Protothecosis (rare)

Prototecosis is a rare disease in dogs caused by an algae. It is not common for dogs to contract this because the algae typically only live in sewage, tree slime, and water troughs for farm animals. However, it can occasionally occur in rivers, lakes, and oceans.

This type of algae is more likely to affect dogs with open wounds who enter bodies of water. Like with HABs, avoid letting your pup play and drink from water that appears slimy or has visible algae.

Cryptosporidiosis (rare)

Cryptosporidiosis is a protozoa and a mouthful to say! Similar to Giardia, dogs usually contract this illness from feces-contaminated water. Protecting your pup from this is difficult because it has a protective outer shell and is resistant to disinfectants like chlorine.

Luckily, it is very rare for dogs to get cryptosporidiosis. 

Schistosomiasis (rare)

Schistosomiasis is caused by a pesky little flatworm most commonly found in the southeastern United States. This ailment is rare in dogs but can be serious.

Texas and Louisiana have the highest number of Schistosomiasis cases, but the disease has been found elsewhere.


Pseudomonas is a bacteria that dogs can ingest when they drink from water sources, especially those found on farms such as horse and cow water troughs. It can also occur naturally in aquifers and other natural water sources along hiking trails.

If a dog contracts Pseudomonas, it typically resembles symptoms of allergies or an ear infection.

🐕Can Dogs Drink From Streams, Rivers, And Lakes?

Pawdrick dog drinking from lake

Now that we know about all the sinister things living in water bodies, should you let your dog drink from them when hiking? There are a few things to consider, such as if your dog is vaccinated against specific water pathogens, what the water looks and smells like, and your dog’s overall health.

Let’s dig in…or should I say dive in?

Stagnant Water: The Danger Zone

Have you ever been out on a hike, exploring the great outdoors with your furry best friend by your side, when suddenly they dart off towards a seemingly harmless puddle or pond for a quick sip? It’s a scene as old as time, but these innocent-looking water sources might be more of a villain in disguise.

Stagnant water acts as an incubator for the unwelcome guests we mentioned above. Without proper water flow, these microorganisms can easily access excess nutrients fed into the water and multiply rapidly. Water can ‘go bad’ or become stagnant in as little as six days. 

Some examples of stagnant water include:

  • Puddles
  • Ponds, swamps, and lagoons with no outflow
  • Water trapped in littered containers, plant containers, old tires, buckets, cans, etc.
  • Water trapped in a hollow tree trunk
  • Any water that is very slow-moving or has no movement at all.

Never let your dog drink water from a stagnant source.

The Look And Smell Of Bad Water

While it’s impossible to positively identify water as clean or bad based on visual observation alone, there are a few signs to look out for (and smell for).

  • Rotten egg smell: This is caused by sulfur bacteria, which isn’t very good for our pups.
  • An oily sheen on the surface of the water + petroleum smell: Most of the time, an oily sheen on the surface of the water is nothing more than natural healthy bacteria attaching to the surface of the water. However, do not let your dog in or near the water if a foul odor or petroleum-like smell accompanies it.
  • The presence of algae in the water: HABs come in many different colors, shapes, and sizes. If there is algae present in the water, it’s better to keep your canine companion away. Better safe than sorry!
  • The presence of dead fish in the water: This indicates there is a pathogen, bacteria, or protozoa present in the water. 
  • Lack of life: If you stand in front of a stream or lake and see no visible animal tracks, no buzzing insects, no birds, or any other signs of life, the water is probably bad.

Flowing Water Is Not Always Fresh Water

Under normal circumstances, flowing water is always safer to drink than stagnant water. The toxins and harmful debris aren’t allowed to build up in flowing water, making it cleaner and clearer.

However, there are some instances where even flowing water isn’t safe for your pup to drink.

  1. The Circle of Life: Imagine a serene stream winding through the forest. Now, imagine an animal has met its fate upstream. This unfortunate event can introduce all sorts of unwanted materials into the water, affecting its purity. While the flow may carry away some contaminants, it doesn’t guarantee the water’s safety for your thirsty pup.
  2. Nature’s Restroom: The great outdoors is everyone’s bathroom—from the smallest squirrel to the occasional hiker who veers off the path. When animals (and yes, sometimes humans) answer nature’s call near or in these water sources, they unintentionally add pollutants that you definitely don’t want in your dog’s drinking bowl.
  3. Unseen Guests: Just because water is moving doesn’t mean it’s free of microscopic party crashers waiting to hitch a ride. These tiny organisms might not affect the scenic beauty of a babbling brook, but they can certainly play havoc with your dog’s health.
  4. Man-Made Mishaps: Our adventures often intersect with areas affected by human activity. Runoff from agriculture, factories, or even just the remnants of an old picnic can introduce substances into rivers and streams that are harmful to our canine companions.

Dog Vaccinations

As pet parents, we all want the best for our canine companions. A visit to the vet for yearly vaccinations is essential to protect your dog from water-borne illnesses like leptospirosis. 

Heartworm medications like Interceptor and Heartgard are given monthly to dogs to prevent multiple types of worms, including heartworm, roundworm, hookworm, and whipworm.

Always consult your vet and let them know if your dog is prone to being exposed to water sources on your outdoor adventures. They may suggest non-core vaccines to help fight off unseen water-borne organisms.

🐾 When Can Dogs Drink From Streams, Rivers, And Lakes Safely?

Gatsby dog looking toward stream

We know that stagnant water is a no-no and that even flowing water isn’t always safe to drink. So, when can dogs drink from streams and other water sources safely?

In reality, it’s impossible to tell if water is truly safe for your pup to drink just by looking at it. However, there are ways to mitigate the risks.

At The Source

If you’re in a bind and need to find water for your dog, try to get as close to the source as possible. If you find a creek, follow it upstream as much as possible. 

The further upstream you go, the closer you are to the source. This is where the water will be cleanest. As the water flows down, it collects pollutants, further contaminating it. Try to avoid the lowest point in a stream or river.

Look For Animal Tracks & Other Life

If your canine companion has his tongue hanging out and you’ve run out of water, look for animal tracks around nearby water sources.

Wild animals have an instinct for when water is or isn’t safe to drink. If wild animals drink from the water source, it’s probably safe for your pup, too.

Another good indicator of a healthy source of water is the presence of life – bugs, lively vegetation, fish, frogs, and other critters. If the water is good enough for these organisms, it’s probably safe to drink.

If you happen to run into a wild animal on your hike, you can read about what to do if you see a black beargrizzly bearcoyotesnakemoosemountain lionwolfbobcatalligatorwild boar, or skunk. Be prepared for any encounter!      

💧How To Keep Your Dog Safe In The Water

Now, we’re all about adventures and making memories with our pets, but we also want to make sure those memories are happy ones! So, how can you keep your furry explorer safe while enjoying the great outdoors together? 

Here are a few tips:

  • Pack Extra Water: Just like you’d bring enough food and water for yourself, pack plenty for your dog, too. Portable dog bowls and water bottles designed specifically for pets make it super convenient to keep them hydrated on the go. The SPRINGER Travel Dog Bottle is a water bottle and bowl combined, making it perfect for your adventures!
  • Watch and Redirect: Keep a close eye on your pooch, especially near tempting but potentially harmful water sources. If they start making a beeline for that murky puddle, gently redirect them back to the clean water you’ve brought. A sturdy leash can help here. We love the Ruffwear Crag Reflective Dog Leash.
  • Educate Yourself: Knowledge is power! Familiarize yourself with the signs of discomfort or illness in dogs, just in case. Early detection can make all the difference. A dog first-aid kit can help here – read about how to build a dog first-aid kit here to keep your furry pal safe!
  • Look For Posted Signs: The Environmental Protection Agency (EPA) and the National Oceanic and Atmospheric Administration (NOAA) work in tandem to alert folks to the presence of harmful organisms in the water. Before letting your pup dive in a lake or river, check for signs that warn of HABs or high bacteria levels. If an area is closed to swimming, there’s probably a reason.

In the end, it’s all about striking a balance between having fun and staying safe. Our pets rely on us to make the best decisions for their well-being, and by taking a few simple precautions, we can ensure that every adventure is a tail-wagging success.

Wrapping Up Our Watery Journey

Bringing our dogs on our outdoor adventures is a special time to bond with our four-legged companions and to give them a full, happy, enjoyable life. But trekking outdoors comes with its own hazards, including drinking from wild water sources.

Ultimately, the answer to the question, ‘Can dogs drink from streams, lakes, and rivers?’ is about risk. If your dog is vaccinated for leptospirosis, and the water is flowing rapidly, you are probably safe. However, to be completely safe, pack your own water and avoid letting your dog drink from streams and other water sources while hiking.

Always look for signs that the water is unsafe, such as a foul odor, the presence of algae, or an oily sheen accompanied by the smell of petroleum. For the cleanest water, aim as far upstream as possible and for high flow rates (fast-moving).

With these tips in mind, you and your canine companion can enjoy your hike knowing that you’re well-armed with knowledge about streams, lakes, and rivers. Happy hiking!

Check out our hiking blog for more tips about hiking with your dog!


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