Is it safe for dogs to drink from lakes and puddles?

Estimated Reading Time 3 minutes
Is it safe for dogs to drink from lakes and puddles?

It’s always a good idea to bring a couple of snacks and water along when going out with your dog. Although dogs can drink untreated water from a lake, from puddles in the street, or from rain, this is not recommended and can sometimes put their health at risk. Read on and find out why.

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Can dogs drink untreated water?

While most animals can drink water from any source, the water from lakes or rainwater puddles, for example, might not be the best for your pet. Caution should also be taken when it comes to stagnant water in the street or at home. And these reasons are practically the same as those that we apply to select the water source humans drink from - we want to avoid dirt, toxic substances, and germs that could cause diarrhea and other health problems.

Can drinking from lake water or puddles make dogs sick?

By drinking untreated water, dogs can be exposed to certain diseases. Below is a list of the most common illnesses caused by drinking stagnant or untreated water.

1. Giardia

Giardia is a protozoan that causes what is sometimes called "beaver fever" in humans. When dogs contract the parasite, they experience mostly stomach symptoms: foul-smelling, intermittent chronic diarrhea, weight loss, and vomiting that can leave the dog dehydrated.

Dogs can become infected with giardia by drinking untreated water from lakes, rivers, and even from standing puddles and rainwater.

2. Leptospira

The Leptospira bacteria can be found both in the soil and water, although infections seem to be more numerous from the latter. Like humans, dogs can become infected by drinking water from a lake, river, stream, and other contaminated sources.

The symptoms of leptospirosis include fever, muscle tenderness, vomiting, diarrhea, and lethargy, but it can also lead to kidney failure and/or liver failure.

3. Cryptosporidium

Cryptosporidiosis is caused by a protozoan called Cryptosporidium. Both wild and domestic animals can excrete it in their feces and contaminate water sources such as lakes and rivers. This infection usually causes diarrhea in dogs.

4. Escherichia coli

Escherichia coli is another bacteria dogs can contract from drinking untreated water, especially from lakes and ponds. The symptoms of E. coli infection include diarrhea and stomach pain, but it can also cause urinary and ear infections. It’s worth noting that pets can also contract E. coli by swimming in contaminated water.

5. Pythium insidiosum

Pythium insidiosum is a water mold that causes a disease called pythiosis. Its symptoms are vomiting, diarrhea, consequent weight loss, and suppurating wounds that are difficult to heal. This mold is common in ponds, swamps, and lakes, so dogs that drink untreated water directly from these sites and be at high risk of contracting it.

Other Dangers Found in Untreated Water

Cyanobacteria (Blue-Green Algae) in Lake Water

Cyanobacteria, better known as blue-green algae, is another danger that dogs are exposed to when drinking untreated water. These are microscopic bacteria that give a pea soup appearance to the surface of lakes. Not all of them are toxic, but when they are, just a few gulps of contaminated water can be deadly to a pet. Blue-green algae is found in freshwater lakes, streams, ponds, and brackish water ecosystems.


Antifreeze is a substance used to regulate the temperature of your car’s engine, so it is common to find it on the pavement. On a rainy day, the water can drag it and stagnate, looking very attractive to a thirsty dog; and although its flavor and aroma are sweet, it is best to avoid drinking this mixture.

Dogs can drink untreated water from a street puddle and, at the same time, ingest antifreeze, which is poisonous. Even a tiny sip could cause irreversible kidney failure and death.

Always Consult a Veterinarian

In conclusion, dogs can drink untreated water, but this exposes them to many risks that can easily be avoided. So, to hydrate your dog on the go, it's best to bring bottled or filtered water from home.

Read more:

Can Dogs Get Sick From Drinking Too Much Water?

Can dogs drink flavored water?

Can dogs eat ice?

Need to speak with a veterinarian regarding your dog’s water source or another condition?

Click here to schedule a video consult to speak to one of our vets. You can also download the FirstVet app from the Apple App Store and Google Play Stores.

Published: 4/18/2022
Dr. Sheena Haney, Veterinarian

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