Should I Give My Dog or Cat Filtered Water?

Summers are getting warmer every year, and with those high temperatures come warnings to keep hydrated and drink enough water. But even as we take extra care to hydrate ourselves and our families well, we could be overlooking another family member’s hydration. Yeah, we’re talking about our cats, dogs, and other pets buddies that rely on us to keep them safe, fed, and healthy.

Our animal family all dehydrate just like humans. They need one ounce of water per pound of body weight every day and even more when it’s especially hot outside — particularly as the thermometer seems to tick higher with every passing summer. Dehydration in dogs and cats can look similar to dehydration in humans as well, with symptoms like weakness, dry nose and mouth, lethargy, and (a more animal-specific sign) a lot of panting. So it’s especially important to keep the water flowing for our canine and feline friends.

But even as we’re more vigilant about whether the family pets are getting enough water, it’s worth considering the quality of that water as well. According to the Environmental Protection Agency, water pollution impacts over 40% of rivers and 46% of lakes in the United States, making it a serious threat to humans and both wild and domesticated animals. Traces from fertilizer runoff, erosion, pollution, and environmental disasters can be found in much water across the United States, even after municipal cleaning processes. 

So if you’ve thought much about your own water quality, perhaps you’ve stopped to ask, ‘Should I give my dog (or cat) filtered water?’ The answer, in short, is yes. Because it’s not just humans that are impacted by water contaminants, but dogs and cats, too.

If you’re on the fence about filtered water for dogs and filtered water for cats, here’s five reasons you may want to think about it.



Thanks to climate change, one occurrence that’s become increasingly common is algal blooms in bodies of water. Essentially, runoff from excess fertilizer and minerals, erosion, and any number of things that can end up in waterways get pushed into streams where they increase what’s called turbidity or the amount of solids floating in bodies of water. That blocks sunlight from the water and (especially if there’s excess nutrients from, say, fertilizer) encourages algal growth.

When these algal blooms grow out of control, they can grow cyanobacteria that possess potent neurotoxins that can make both pets and humans sick with fatal results. For instance, algal blooms in Austin, Texas in 2019 killed several dogs. 

Municipal water treatment takes on the task of removing much of these types of toxins and contaminants from the water supply going to our homes, but can often leave trace elements behind — not to mention it can’t account for the quality of the pipes delivering the water to our properties or those carrying it into our homes, much as Flint, Michigan can attest.



Meanwhile, Ground Water Governance reports that “The presence of calcium and magnesium in tap water can cause crystals in the urine, urinary tract infections, and incontinence.”

In addition to not wanting our pets to suffer, there’s a financial concern as well. The claims being filed through Trupanion are hardly inexpensive. Claim prices for both cats and dogs ranged from a reasonable $77 to upwards of $1200 for diagnosis and treatment. That’s not only an argument for filtering your pets’ water, but one for buying them insurance as well.



Since the crisis in Flint came to the fore in 2014, lead contamination has been in the news once again. And a 2017 study in “The Journal of the American Veterinary Medical Association” (JAVMA) reported evidence that Flint’s lead contamination had consequences beyond the human population, extending even to household pets. Among Flint animals they tested, the “median blood lead concentration for Flint dogs was four times the median concentration in control populations.” According to the report, this elevated level continued even after owners began giving their dogs clean water.

In fact, even small amounts of lead exposure can have a larger impact on animals than on humans. The JAVMA researchers also pointed to a 1994 report from Illinois' Hazardous Waste Research and Information Center that found that dogs and cats “were more likely than their owners to have high blood lead concentrations.” Furthermore, the researchers pointed out, lead is a cause of intermittent seizures in cats.

If you don’t live in Flint, it might be tempting to ignore issues of lead in your water, but consider the EPA’s warning that homes built before 1986 likely have, if not lead pipes, pipes that contain lead. In fact, new pipes, fittings, and fixtures were allowed to hold up to 8 percent lead until 2014, which means even houses built between then and 1986 might have pipes that expose household pets to lead through.



Unfiltered water may also contain iron, which can bring its own host of concerns for dogs. According to veterinary service, Wag, “excess iron acts as a poison in your dog’s body, and causes damage to the gastrointestinal, liver, metabolic, nervous, and cardiovascular systems because the body is not able to expel the iron.” 

Iron toxicity generally occurs if your pet ingests something they shouldn’t — like a dropped vitamin — but if you live in a city with hard water, pets might also be ingesting that excess iron from less obvious sources, like their own bowls of cold, refreshing hard water.