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Is Tap Water Safe For Dogs To Drink?

↯ Key takeaway points

  • Tap water is safe for dogs as long as it's safe for humans.
  • Tap water may contain harmful contaminants and water hardness that may be risky for dogs with frequency of long-term effects.
  • Chlorine in tap water is considered safe but when chlorine mixes with organic material in water, it can form disinfection byproducts that can be harmful in large amounts.
  • Filtered tap water is a good option to provide clean drinking water for dogs.
  • The use of distillation, reverse osmosis or nanofiltration can provide high-quality, contaminant-free water for dogs.
Breeding Business is passionate about all sorts of domesticated pets. They have written dozens of articles across the web.
Zoo and wildlife doctor in veterinary medicine passionate about animal welfare and preventive medicine.
Published on
Friday 27 October 2017
Last updated on
Wednesday 10 May 2023
Is Tap Water Safe For Dogs To Drink?
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Whether you’re a dog breeder or a simple household with a cute family dog, it’s important to know if tap water is safe for your furry friend to drink. The good news is that tap water is safe for dogs as long as it’s safe for humans. However, just because it’s safe doesn’t mean it’s the best option for your pup.

In this article, we’ll compare tap, filtered, and bottled water for dogs, so you can decide which is right for you and your furry friend. Each type of water has its pros and cons, so it comes down to personal preference.

How Safe Is Tap Water For Dogs?

How safe is tap water for dogs? This is not an easy question to answer, as different aspects need to be considered to get the full picture. First of all, we have to consider tap water’s contamination with harmful substances like organic chemicals, bacteria, viruses, heavy metals, and more. Secondly, water hardness can also be a potential danger to the health of dogs, which, strictly speaking, is not a form of water contamination. Last but not least, we shall not forget about water fluoridation, a measure introduced by the U.S. Public Health Service in 1951 to prevent tooth decay among citizens.

Water Contamination

According to 5000 ppm (parts per million) of total dissolved solids in drinking water is considered acceptable for pets, which I don’t fully agree with. Obviously, it’s a difference if drinking water contains 5000 ppm of toxic arsenic or 5000 ppm of sodium. I believe it’s always best to look at the concentration levels of individual water contaminants in respect to the health problems that they can cause:

  • Lead – When swallowed in high doses, lead can cause acute stomach pain, diarrhea, and vomiting in your dog. If exposed over a long time period, your dog might experience seizures, fatigue, poor appetite, extreme anxiety, blindness, and changes in behavior.
  • E. Coli – There are different types of E. coli bacteria, most of which are harmless. However, from time to time, dangerous strains are found in our public water supply systems. A dog infected with E. coli may show some symptoms: lack of appetite, low body temperature, depression, increased heart rate, diarrhea, vomiting, malaise/weakness, and lethargy.
  • Arsenic – Fortunately, it’s rare that arsenic can be found in our tap water in alarming dosages. But if it is and your dog swallows too much of it, it might develop abdominal pain, become lethargic or even lose consciousness.
  • Pesticides – Pesticides are present in almost every water supply system in the U.S. They kill insects, weeds, and fungi that would otherwise destroy or damage the harvest. Long-term effects in humans through direct or indirect exposure are different types of cancer, infertility, birth defects, autism, and other significant illnesses. Health effects on dogs have not been tested yet.

Water Hardness

Magnesium and calcium are minerals that occur in water naturally. If the water contains more than 17.1 ppm of both minerals added together, it is called “hard water”. Trupanion, a veterinary medical insurance company, discovered that areas in the U.S. that are provided with extremely hard tap water (more than 240 ppm) have a “significantly higher risk of pets running into urinary health issues“, which includes tract infections, incontinence, cystitis, and crystalluria.

Water Fluoridation

High fluoride intake associated with increasing health issues among dogs is a connection that has yet to be demonstrated. By the way, U.S. tap water contains 0.7 ppm of fluoride only. However, the Environmental Working Group found that, depending on the brand, dog food may contain fluoride 2.5 times higher than the maximum legal dose in drinking water. In other words, before you rack your brain over fluoride in water, spending your energy on finding a trustable brand for fluoride-free dog food is more advisable.

filtered water for dogs
Filtered tap water for dogs to drink is a great compromise. Tap water has too many risks while bottled water is definitely overpriced.

Is Chlorinated Tap Water Bad For Dogs?

Did you know that the water running from your kitchen and bathroom taps contains bits of chlorine? This is because chlorine is highly effective in killing harmful germs and protecting us from water-borne diseases. But what about your furry friends? While no scientific study has been conducted on the health effects of chlorinated water on pets, it’s important to remember that the dose makes the poison.

In other words, the risk of harm depends on how much and how often your dog drinks chlorinated water. Chlorine itself is considered safe in drinking water in the amounts used by municipal water companies that don’t exceed regulatory guidelines set by the federal government. However, when chlorine mixes with organic material in water, it can form disinfection byproducts that can be harmful.

Inhaling chlorine gas can irritate the airways, sore throat, coughing, chest tightness, breathing difficulties, and bronchospasm. Drinking water with high amounts of dissolved chlorine can cause burns to the tissues of the gastrointestinal tract. Long-term ingestion of chlorinated water has been linked to an increased risk for bladder cancer in both men and women.

The Dose Makes The Poison

The dose makes the poison, and that goes for chlorine, too. To identify a potential risk, it’s important to know how long and how often a dog drinks chlorinated water, and how much of it. In general, the halogen is considered safe in drinking water in the amounts used by municipal water companies that don’t exceed regulatory guidelines set by the federal government. But studies have also shown that water treated with chlorine is dangerous not for the chlorine itself, but for the disinfection byproducts that form, when it’s mixed with organic material.

We all know what chlorine smells like. That’s because it’s gas and, if inhaled, can cause airway irritation, a sore throat, and a cough. In more severe cases, inhaling chlorine can lead to chest tightness, wheezing, breathing difficulties, and bronchospasm. Moreover, as with many other substances, chlorine causes adaptation, meaning that once it’s in your nose, your ability to smell it gradually decreases. If you drink water with very high amounts of dissolved chlorine, you might experience burns to the tissues of your gastrointestinal tract. Regarding long-term effects, scientists could prove that ingesting chlorinated water is associated with an increased risk for bladder cancer in both men and women.

Tap Water vs Bottled Water For Dogs

As a responsible dog owner, you know about the dangers that contaminated drinking water can hold for Daisy or Buddy. If and how chlorine-treated tap water affects the well-being of your dog in the long run is hard to say at this point, but science suggests that it’s probably better to avoid it if you can. This leaves you with 2 options. The first option you have is to serve your dog bottled water. How it performs compared to tap water depends, first and foremost, on the type of bottled water you buy. In the average supermarket, you can find:

  • Artesian bottled water, which comes from a natural aquifer
  • Distilled bottled water can be drawn from almost any source and has been boiled and condensed to remove impurities
  • Mineral bottled water which is a form of groundwater and has to contain at least 250 ppm of total dissolved solids
  • P.W.S. (Public Water Source) bottled water, also known as tap water
  • Purified bottled water that comes from any source but was treated to reduce the total dissolved solids below 10 ppm
  • Sparkling bottled water that comes from a well or spring and naturally contains carbon dioxide
  • Spring bottled water comes from an underground source and, due to pressure, flows to the surface

If you buy expensive bottled water, which costs a hundred times more than regular tap water, make sure it’s not just water from a public water source that was filtered and then filled into a bottle. Because that is – and there is no other word for it – a complete ripoff. Instead, look out for sparkling or mineral bottled water. If you have the budget, go for spring and artesian water, the most natural type of water and usually contains zero harmful contaminants. And always choose a glass container over plastic, or if that’s impossible, go BPA-free.

FYI: The drinking water standards for bottled water set by the FDA are even lower than standards that regulate tap water quality. So definitely choose a bottled water brand you can trust 100 percent. The best scenario would be if the water is monitored and regularly tested by a third party.

Tap Water vs Filtered Water For Dogs

The alternative to bottled water – and it’s my personal favorite – is to serve your dog tap water that you’ve cleaned with your own filter system at home, usually in the kitchen or in the bathroom if you prefer. The advantages of filtering your own drinking water are evident. More than anything, if you apply the right filtration technology, the water purity you can achieve can only be compared to high-quality spring or artesian water in a glass container. Chances are that your dog doesn’t like it as much because the water has a very mild taste, but compared to plain tap water, it will definitely benefit his health, and that’s the priority. Second, to have access to clean drinking water, you no longer have to rely on your local water supplier or any other external party and hope that they respect and meet regulatory standards.

Filtration Technology

Not every filter system uses the same technology to clean water. The most commonly used technologies are distillation, reverse osmosis, and mechanical filtration (microfiltration, ultrafiltration, or nanofiltration). A distillation and a reverse osmosis system provide drinking water of the highest purity. The two systems can remove bacteria, viruses, antibiotics, salts, flavors, and more. In the case of mechanical filtration, a microfiltration system might be barely able to remove larger viruses but definitely fails when it comes to antibiotics or ions. Ultrafiltration already performs better, but a nanofiltration membrane has the smallest pores and delivers the best performance among the three.

If you want to remove as many contaminants as possible from your drinking water, consider using a distiller or a reverse osmosis system. These systems can be more expensive and require additional maintenance, but they can provide high-quality, contaminant-free water. Remember that tap water is safe to drink in most areas, and filtering is not always necessary.

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