Most dogs have taken a drink from a river, lake, or pond at some point in their life, and many pet parents assume that dogs are not capable of getting sick from doing so. Unfortunately, this is not true. Just as a human could get sick from the bacteria in unfiltered water, dogs can get sick as well. Although drinking from an external body of water does not guarantee your pet will get sick, it does pose its fair share of risks.
Protozoans are microscopically small organisms that live in unfiltered water. They include species such as Giardia and Cryptosporidium, which can wreak havoc on a dog’s digestive system, often causing vomiting or diarrhea. In extreme cases, these organisms can cause intestinal bleeding and death. Although protozoans are present in most unfiltered water, healthy dogs are capable of carrying the parasites without getting sick or showing symptoms. Dogs that are very young, very old, or have a weakened immune system, however, are much more likely to get sick.
If your dog is drinking from something like an irrigation ditch, a pond surrounded by agricultural land, or a puddle in the middle of a field, there is a good chance the water is contaminated with chemicals. Chemical run-off occurs when substances such as pesticides and insecticides wash off farmland and settle in nearby bodies of water. The concentration of chemicals can vary depending upon the size and movement of the water body, but even a small amount can make your dog sick.
Particularly common in ponds and stagnant bodies of water, algae is a small plant-like bacteria species that grows on the water’s surface. Algae is typically more prevalent during the summer and fall months and has many different appearances. When dogs swim in a pond or another stagnant body of water, there is a chance of them swallowing algae.
This chance is increased if the dog is swimming with their mouth open while fetching or if they tend to bite at the water while swimming. Even grooming his coat after a swim may result in your dog ingesting blooms of algae. Some algae-borne toxins may affect the nervous system or lead to liver failure and even death. There are no antidotes to these toxins, but your veterinarian can offer supportive care to your pooch, so if he has swallowed algae, you should take him to the vet as soon as possible.
Outdoor water can be contaminated with a range of other bacteria as well, which are introduced through human or animal waste or sewage entering the water. Some bacteria merely cause diarrhea (how's that for a best-case scenario?), but there are more dangerous bacteria that can lead to kidney failure, liver damage and death. Such bacteria include Campylobacter, Salmonella, E. coli and Leptospira. The latter can be passed on to humans through an infected dog's urine and cause the zoonotic disease leptospirosis. There are Leptospira vaccines, however, which can help to protect your dog from some strains of the bacteria, so if you spend a lot of time out in the wild with your dog, consult your veterinarian about the available inoculations.
How to Prevent Your Dog from Drinking Bad Water
Hiking is just as tiring and dehydrating for your dog as it is for you. If he comes across any water, he may be tempted to quench his thirst right there, so always make sure that you have clean and safe water available as an alternative to rivers or ponds. Whenever you take your dog on a hiking or camping excursion, remember to pack his portable water bowl. If you see him heading for a lake or stream, pour some fresh water into his bowl and lead him to drink that instead.
Of course, dogs are inclined to wander and explore all the smells in the great outdoors and you may not be able to keep an eye on your pup at all times, so it is important for you to know the signs of water-borne complications and the harm they can cause. If your dog seems strange and listless after a trip, or displays any symptoms such as vomiting, lethargy, diarrhea or fever, take him to your veterinarian immediately.
Content reviewed by a veterinarian