Get

In Your Inbox

Catster is reader-supported. When you buy via links on our site, we may earn an affiliate commission at no cost to you. Learn more.

Can Hard Water Cause Urinary Crystals in Cats? Vet Approved Facts & Advice

cat drinks water

Keeping your pet safe and in good health is an essential part of taking care of a cat. Unfortunately, there are times when your pet might become ill regardless of your best efforts.

The chance of your cat dealing with conditions like urinary crystals typically depends on factors like their age, breed, and diet, but can hard water cause crystals in the bladder?

One 2016 data release did discover a potential association between hard water and urinary crystals in cats1. However, there is no targeted, scientific data to back up these claims.

Here’s information about hard water and urinary crystals and whether you should be worried about your cat’s bladder.

divider 3 paws

The Study

On April 7, 2016, pet insurance company Trupanion released a report that examined the link between hard water and urinary crystals in pets2. It used data from the Environmental Protection Agency that enabled the researchers to compare U.S. cities with hard water to the claims put through Trupanion for pets with urinary problems.

Statistics

It was found that studied cats were 40% more likely to experience urinary problems than studied dogs. Additionally, male cats were 1.5 times more likely to encounter urinary problems than female cats.

The highest claimed urinary conditions among cats were:

  • Urinary tract infections
  • Cystitis
  • Urinary obstruction
  • Crystalluria

Hard Water

It was also discovered that U.S. cities with “extremely hard water” had a much higher rate of urinary health claims, with an emphasis on crystalluria, which are the crystals found in cat’s urine3. The male cats in these cities were found more likely to have urinary conditions than those in cities with “slightly hard,” “hard,” or “very hard” water.

Trupanion used the example of Florida, which it classified as having “extremely hard water.” It encountered 10 times the number of claims in Florida than in the other states. The other cities listed as having “extremely hard water” were Chicago, Detroit, Cincinnati, Miami, and Minneapolis.

However, the statistics and information from this report are now over 7 years old. If you want to determine if you live in an area with hard water, check your region’s water-quality report.

Woman filling glass with tap water from faucet in kitchen
Image Credit: New Africa, Shutterstock

divider 3 paws

What Exactly Are Urinary Crystals?

Urine contains solid waste particles, which turn into more solid particles like crystals when the concentration of waste products is high enough. These crystals get bigger and may eventually become stones, which may continue to increase in size if not treated.

Bladder stones can lead to urinary tract infections or a urinary tract blockage, which needs immediate medical intervention!

Causes

It’s not entirely known what typically causes urine crystals, but the following are considered the potential contributing factors:

  • Breed
  • Sex
  • Age
  • Diet
  • Certain health conditions

Signs

The common signs for cats with urine crystals and bladder stones are:

  • Straining to urinate
  • Increased urination
  • Only urinating tiny amounts of urine
  • Urinating outside of the litter box
  • Blood in the urine

If your pet is showing these signs, we suggest you speak to a vet.

If you need to speak with a vet but can't get to one, head over to PangoVet. It's an online service where you can talk to a vet online and get the advice you need for your pet — all at an affordable price!

PangoVet_Mention-in-Content for PangoVet2 save money

Treatment

Female cats can sometimes pass very small stones on their own or with flushing, but male cats tend to have more trouble passing them.

Some stone types can dissolve through a prescription diet, but if they are too large, they need to be removed via surgery. If a blockage occurs, this is a life-threatening emergency that will often require a cat to be hospitalized for a few days.

Cat sitting on a vet metal table
Image Credit: Tyler Olson, Shutterstock

What Makes Water Hard?

The main culprits that can cause hard water are calcium and magnesium. While these minerals benefit our health overall, excess dissolved magnesium and calcium can damage equipment (like dishwashers) and dry out skin and hair.

divider 3 paws

What If You Have Hard Water?

It isn’t an absolute certainty that if your cat drinks hard water, they are automatically vulnerable to urinary crystals. There haven’t been any peer-reviewed studies on the matter.

That said, the statistics that Trupanion gathered might still be something to take into consideration when you’re supplying your cat with water, particularly if you have a male cat, since males are more susceptible to urinary crystals.

1. Water Softener

You can invest in a water softener for your home or a small ion-exchange water filter that can be attached to your tap. This is the best way to remove the excess minerals that lead to hard water.


2. Boiling the Water

Boiling spaghetti in pan on electric stove in the kitchen
Image Credit: Africa Studio, Shutterstock

A more complicated route is boiling the water that you need.  It needs to be boiled for several minutes, cooled, and then poured through a sieve or cheesecloth to remove the minerals boiled out. It is not as effective as other methods.


3. Water Filters

Unfortunately, most water filters don’t remove as many of the excess minerals as water softeners do. These include cat fountains with charcoal filters.

However, water filters can remove some of the excess impurities from tap water and are still good options, particularly if you can’t afford a water softener.


4. Bottled Water

cat resting near bottled water
Image By: MVolodymyr, Shutterstock

Bottled water is considered soft water because it contains low levels of magnesium and calcium, which makes it a viable option for your cat.

Just don’t bother with distilled water, as there haven’t been any studies that say that it’s safe to give distilled water to your cat as their only water source. It won’t harm your cat, but since it doesn’t contain any minerals, it isn’t necessarily beneficial either.

divider 3 paws

Conclusion

Although the data for cats at present remains lacking, if you live in an area that has been classified as having “extremely hard water,” it might be in your best interests to invest in a water softener. The water might not affect your or your cat’s health, but it will undoubtedly damage some of your major appliances.

Overall, there don’t seem to be any serious human health risks associated with drinking hard water, including urinary crystals, but more studies need to be done on the effects of hard water on cats.


Featured Image Credit: AltamashUrooj, Shutterstock

Want content like this delivered to you?

Sign Up For Our Newsletter

News, insights, expert advice, and everything cat

* By submitting, you agree to our Terms & Conditions and Privacy & Cookies Policy.

How useful was this post?

Click on a star to rate (you can leave written feedback after clicking submit)

Help us improve Catster for pet parents!

Your feedback really matters.

What did you like about this post? Also how can we improve it?

Join the conversation

Leave a Reply

You’re very welcome to leave a comment or question. Please know that all comments must meet our community guidelines, and your email address will NOT be published. Let’s have a positive and constructive conversation.

Talk With A Vet Online

Peace of mind,
anywhere, anytime

Affordable vet advice

Why Do Cats Bring You Their Toys? 8 Vet-Approved Reasons & FAQ

When you think of a pet bringing you toys to play with, you probably picture the wagging tail and doleful eyes of your...

Is Cat Yoga Ethical? Pros, Cons & Ethics (Vet-Reviewed)

You’ve maybe seen influencers on Instagram or videos of yogis on TikTok holding yoga postures while goats or dogs climb all over them....

Why Do Cats Stare? Feline Behavior Explained (Vet-Reviewed Info)

If you’ve ever watched your cat mesmerized for minutes or longer by a seemingly random object, you’re not alone. Since time immemorial, humans...

10 Vet-Reviewed Tortoiseshell Cat Health Problems & Care Tips

A tortoiseshell cat isn’t a separate breed. Tortoiseshell is a color that can appear among quite a few cat breeds. This gorgeous pattern...

More related

Living With Cat Allergies — 8 Vet-Approved Tips & Tricks

Cats are wonderful, loving animals that can bring a great deal of joy and enrichment to your life. Unfortunately, though, some people are...

How Far Can Cats Travel in a Day? Facts & FAQ

Big wild cats roam vast territories daily to find prey, keep out competitors, and generally keep an eye on their land. The average...

Can Kittens Eat Adult Cat Food? Vet-Approved Timeline & Transition

If you have a multi-cat home, you may encounter your new kitten lapping up some of your adult cat’s food, or perhaps you...

Are Savannah Cats Good Pets? Pros & Cons

Savannah cats are created by breeding domestic cats with wild African Serval cats. These felines are beautiful, but their “wild” side must be...

Keep reading

Feline Leukemia Day 2026: What It Is & How To Participate

There are many wonderful pet holidays every year, such as Walk Your Pet Day and Cuddly Kitten Day. These holidays can be fun and help us bond with our pets. However, few of these holidays are as important as Feline...

vet checking up a cat

How Far Apart Can Kittens Be Born? Vet Verified Facts

The amount of time a cat is in labor varies, but most kittens can be born between minutes to about an hour apart. Sometimes, mother cats can go into interrupted labor and stop straining between 24 to 36 hours before...

mother cat and its kittens

Does UV Light Kill Fleas on Cats? Vet-Reviewed Effectiveness, Safety & Alternatives

Fleas are pernicious little parasites, and it can be hard to get rid of them on your cat. This fact has given rise to the rumor of UV light killing fleas, but is it true? UV light can technically kill...

Lamp ultra violet

Why Do Cats Use Litter Boxes? Vet-Verified Facts & FAQ

You might be quite impressed with your cat’s ability to check out a tub of litter one time and know exactly what to do with it. Why can’t dogs be like that? Even though we’re super impressed with our felines’...

Ginger cat sitting in a litter box

Can Cats Eat Caviar? Vet-Verified Benefits & Precautions

Have you ever wanted to give your cat an expensive treat, like caviar (raw fish eggs)? Before you open up the caviar jar, you want to make sure that it is safe. Cats can eat caviar, but it is not...

Can Cats Eat Caviar

4 Angry Cat Sounds & Vet-Approved Tips on How to Calm Them

Cats often express their emotions—which can include anger and aggression—through various sounds. If your cat is making angry sounds that have you worried, it’s important to understand the cause and find ways to calm them down. Keep reading while we...

abyssinian cat hisses

8 Best Cat Foods in Australia of 2026 – Reviews & Top Picks

One of the most important things that you can do to help ensure that your cat lives a long and healthy life is to feed them a high-quality diet. As the old saying goes, “You are what you eat,” which...

persian cat eating dry food from bowl

Is Chamomile Poisonous to Cats? Vet Approved Facts & FAQ

Many cats love to explore the great outdoors—stalking mice, or hiding among the flowers and shrubs of your garden, nibbling away at any plant that entices them. A popular plant your cat may come across on their garden adventures is...

Catster_Is Chamomile Poisonous to Cats