Lots of dogs seem to enjoy a refreshing drink from a mud puddle, but is this practice safe for your dog? The short answer is: no. Some mud puddles harbor a protozoan parasite called Giardia. When another animal is infected with Giardia, their feces will contain the cyst form of the parasite. If a dog drinks from a water source contaminated with animal feces infected with the Giardia cyst, he may develop giardiasis. The most common symptom of giardiasis is diarrhea and possible weight loss. Your veterinarian will do a microscopic exam on a stool sample from your dog or cat to diagnose giardiasis.
Puddles of water outside may have other contaminants such as fertilizers, pesticides, antifreeze and other dangerous chemicals which your dog should not ingest. Stagnant water may also contain bacteria, viruses, parasites and fungus which can be dangerous for your pet.
It may not be possible to completely prevent a determined dog from drinking from dirty water sources. However, you can reduce the likelihood by always providing a plentiful supply of clean, fresh drinking water. Bring a water bottle and portable water dish with you when walking your dog so you can provide a drink of fresh, healthy water to your dog if he becomes interested in drinking from mud puddles.