Can cats drink tap water?

Yes. Cats can drink EPA-compliant tap water. The most common issue is palatability, not safety. Some cats refuse chlorinated water, which can lead to dehydration. A pet water fountain with a carbon filter, or a pitcher of filtered water, solves this without addressing a health risk. If your cat drinks well water, test for bacteria and other contaminants as you would for your household.

Does chlorine in tap water hurt pets?

At tap concentrations, free chlorine is not a documented health risk for cats or dogs. The primary issue is taste, some animals won't drink chlorinated water, which matters more for cats, who often don't drink enough as it is. Fish are a different matter: chlorine and especially chloramines are toxic to fish even at tap concentrations. For dogs and cats, palatability is the concern, not toxicity.

Is fluoride in water toxic to dogs?

The claim that fluoride in tap water is toxic to dogs is based on a misunderstanding. Sodium fluoride, a different compound used in some rat poisons, is acutely toxic to dogs at high doses. The fluoride compounds used in water fluoridation (typically sodium fluorosilicate or fluorosilicic acid, which convert to fluoride ion in solution) at EPA-regulated concentrations (below 4 mg/L) are not associated with documented health effects in dogs.

What water is best for dogs?

For most dogs, EPA-compliant tap water is appropriate. If your dog won't drink chlorinated water, a pet fountain with a carbon filter or a pitcher of carbon-filtered water is a practical solution that addresses palatability. If you're on a well that hasn't been tested for bacteria, test it. If you have lead pipes and haven't tested your tap, a $15 lead test gives you a clear answer before you worry further.

Is Tap Water Safe for Dogs and Cats? What Pet Owners Should Know

Q: Is tap water safe for dogs?

EPA-compliant tap water is generally fine for healthy dogs. The same contaminant concerns that apply to humans apply to dogs, just scaled by body weight and daily water intake. A 70-pound dog drinking 2-3 cups per day has a different exposure profile than a 10-pound dog that drinks less. Chlorine, fluoride, and typical hardness minerals at tap concentrations are not documented health risks for dogs.

EPA-compliant tap water doesn’t pose known risks to healthy dogs and cats. The same contaminant concerns that apply to people apply to pets, scaled roughly by body weight and daily water consumption.

Most of the questions pet owners have about tap water come from online sources that overstate risks or confuse different compounds. Here’s the accurate picture for the most common concerns.

Chlorine and Chloramines

The most common concern from pet owners is chlorine. At tap concentrations, free chlorine is not a documented health risk for cats or dogs.

The main issue is palatability. Some animals, particularly cats, refuse to drink water that tastes like chlorine. This leads to dehydration, which is a real health concern for cats in particular. The solution is taste, not toxicity: a pet fountain with a carbon filter, or a pitcher of carbon-filtered water sitting at room temperature, solves the problem.

Chloramines (used by about half of US water utilities instead of or alongside chlorine) don’t off-gas just by letting water sit overnight, the way free chlorine does. If your dog or cat seems to avoid tap water and you know your utility uses chloramines, a carbon-filtered water source addresses both chlorine and chloramine palatability.

Fish are a completely different case. Chloramine is toxic to aquarium and pond fish at tap concentrations. Never add untreated tap water to a fish tank. For dogs and cats, palatability is the issue. For fish, it’s a toxicity issue.

Fluoride: Clearing Up the Confusion

The “fluoride is toxic to dogs” concern circulating in pet communities is based on a specific compound: sodium fluoride, which is used in some rat poisons and is acutely toxic to dogs at high doses.

The fluoride in tap water is a different matter. Water fluoridation uses sodium fluorosilicate or fluorosilicic acid, which convert to fluoride ion in solution. At EPA-regulated concentrations below 4 mg/L, and at the HHS-recommended fluoridation level of 0.7 mg/L, there’s no documented evidence of health effects in dogs or cats.

If you’re still concerned, a reverse osmosis system removes fluoride. But the specific claim that tap water fluoride causes thyroid disease or bone cancer in dogs is not supported by current veterinary research at normal tap concentrations.

Heavy Metals

Lead affects pets the same way it affects people. If you have lead pipes or solder and haven’t tested your tap, that’s worth knowing.

A certified lead test costs $15-30. If lead is present, an NSF/ANSI 53-certified filter addresses it. The concern is more relevant to small dogs and cats because of body weight scaling.

Copper is a specific concern for shrimp and aquatic invertebrates, not for dogs and cats at typical tap concentrations. Some copper piping can leach elevated copper after long stagnation periods, but this is addressed by flushing cold water before drawing it.

Well Water and Bacteria

Pets are more likely to develop GI problems from bacterial contamination than from chemical contaminants at typical levels.

If your well has never been tested for E. coli and coliform bacteria, or if your dog has had recurring stomach upset on well water, testing the water is a reasonable step. A basic coliform test costs $30-50 at a county-certified lab.

This is especially relevant if your property has livestock, if your well is older, or if your area experienced significant flooding in the past year. Flooding can introduce surface contamination into a well that otherwise tests clean.

Pet Water Fountains

Pet water fountains are good for increasing water intake, particularly for cats. Most include a small carbon filter for taste improvement. They don’t remove lead, PFAS, nitrates, or any health-effect contaminant.

If you’re already filtering your household water for health reasons, filling the pet fountain from filtered water makes sense. If your tap is otherwise fine and your only concern is palatability, the fountain’s built-in filter handles that.

When to Actually Filter for Pets

Two situations where filtering specifically for pet health makes sense:

If you have a small dog or cat (under 15 pounds) in a pre-1986 home with lead pipe risk, the body-weight scaling makes lead more of a concern per unit intake. An NSF 53-certified filter at the kitchen tap addresses this.

If your well tests positive for bacteria, NSF/ANSI 55 Class A UV disinfection or boiling provides protection for pets as well as household members.

For healthy dogs and cats on tested, EPA-compliant tap water, taste palatability is usually the actual issue, not a health one.

The Bottom Line

If your dog or cat won’t drink the tap water, a carbon-filtered fountain or pitcher solves the palatability problem without needing to address a safety concern.

If you’re on a well and it hasn’t been tested recently, test it. That applies to your pets’ water the same as yours.

For most households on city water with an otherwise normal home, your tap is fine for pets.