Fact or Fiction: Does Hard Water Cause Kidney Stones?

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Kidney stones are tiny yet extremely painful formations of minerals and salts within the kidneys, affecting millions of people worldwide. They vary in size and symptoms may range from nausea, sharp back pain to discolored urine.

Amidst the factors that contribute to kidney stone formation, one question some have is, does the water we drink play a role?

In this article, we dive into how kidney stones form and answer this question. Fact or fiction: does hard water cause kidney stones?

📌 Key Takeaways

  • Kidney stones are deposits of minerals and salts that form inside the kidneys.
  • Drinking hard water does not cause calcium kidney stones
  • The most important thing to prevent urinary stone disease is drinking adequate water (regardless of if it’s soft or hard water).

🧐 What are Kidney Stones?

Kidney stones are deposits of minerals and salts that form inside the kidneys, creating hard crystals. These crystals vary in size and are very painful. Typically symptoms will begin when the stone moves around or enters the ureters.

The most common symptoms may include sharp pain below your ribs on your back and side, pain or burning when urinating, discolored urine, blood in urine, nausea, and vomiting.

As long as they are caught early, kidney stones rarely cause permanent damage. Depending on the situation, treatment may include proper hydration and pain medications or surgery depending on the circumstance.

Man suffering from kidney stones

🔎 How Do Kidney Stones Form?

Stones are typically formed when there are more substances such as calcium, uric acid or oxalate than the fluid in your urine can dilute.

When urine becomes concentrated, this allows the minerals in the urine to crystallize and stick together. There are a variety of different types of kidney stones including calcium oxalate stones, uric acid, cystine stones, struvite stones.

Calcium oxalate stones are the most common type of kidney stones. These stones can be formed due to inadequate fluid intake and inadequate calcium intake. This is because calcium binds to oxalate in the gut, hindering its absorption.

When there is not enough calcium in the diet, oxalate and calcium do not bind in the gut. This leads to more absorption of free oxalate and therefore more oxalate excreted via urine. More oxalate in the urine leads to an ideal environment for kidney stones to occur.

Research shows a diet low in calcium increases your risk for kidney stone formation.

Risk Factors for Developing Kidney Stones

While there are no definitive, “single” root causes for kidney stones, there are several factors that put you at higher risk for developing them.

  • History. If you have a personal or family history of kidney stones, you’re more likely to develop kidney stones in the future.
  • Dehydration. When you don’t drink enough water day after day this also increases your likelihood of kidney stone formation.Certain climates that are hot and dry may put you at higher risk for dehydration and therefore higher risk for stone formation.
  • Dietary habits. If you eat food that is high in sodium, sugar or protein this may also increase your risk for developing certain kinds of kidney stones. High sodium diets result in an increased amount of calcium your kidneys have to filter and increase risk for developing stones.
  • Medications or supplements. If you take certain dietary supplements, laxatives (if you used in excess), calcium antacids, and other medications such as those that treat depression can also increase your risk for kidney stone formation.
  • Obesity. An elevated body mass index (BMI) has been linked to increased risk for kidney stones.
  • Certain digestive conditions. such as short gut syndrome, inflammatory bowel disease and history of gastric bypass surgery cause changes to the way you digest that affect your absorption of calcium and water. This increases the amount of those crystal forming substances in your urine.
  • Certain medical conditions. Renal tubular acidosis, hyperparathyroidism, cystinuria, and recurrent urinary tract infections may also increase risk.

🚱 What is Hard Water?

Water that has a high level of dissolved minerals is called hard water. The minerals that typically contribute to water hardness are calcium and magnesium.

However, ferrous iron, chloride and sulfate and trace amounts of metals may also be present.

Hard water buildup on faucet

🤔 Is There a Link Between Kidney Stones and Hard Water?

You may ask yourself, if there is higher amounts of calcium in hard water, does this mean it can increase the likelihood of kidney stone formation? The simple answer is no, there is not enough evidence to support this at this time.

As mentioned earlier, research demonstrates that inadequate calcium intake is correlated with an increase in stone formation. On the flip side of that coin, there is some research that demonstrates that high doses of calcium outside of meals times may also lead to increased stone formation.

However, there is limited research to support a correlation between hard water consumption and kidney stones. Most hard water contains about 50 to 75 mg calcium and daily recommended intake of calcium is 1000-15300mg per day. It is unlikely that someone who drinks hard water would significantly over consume calcium to increase likelihood of stone formation.

While there have been a few studies that have suggested a link between hard water consumption and kidney stone prevalence, most of these studies are outdated and do not demonstrate causation.

In fact, whether you drink hard water or soft water the most important thing is that you drink plenty of water to prevent dehydration. This will significantly reduce your risk of developing kidney stones.

📝 Ways to Prevent Kidney Stones

So, how do we prevent kidney stone formation? Well, we can prevent them from forming by decreasing our risk factors.

There are some we may not be able to control such as family history or certain medical conditions. However, we can certainly address other modifiable risk factors such as fluid intake and diet.

See below for ways to reduce your risk of kidney stones.

  • Stay hydrated. Drinking plenty of water will help dilute your urine. Make sure to drink at least 64 oz of water daily.
  • Reduce your intake of salt, sugar and protein.
  • Eat more fruits and vegetables.
  • Weight loss may be helpful if you’re overweight.
  • If you have recurrent kidney stones or kidney stone disease, talk to your doctor about any medications or supplements that may be contributing.
Woman drinking sole water

📑 Conclusion

In this discussion surrounding kidney stone etiology, the relationship with hard water seems to be used as a marketing technique for companies that sell water softeners. If you prefer soft water for other reasons such as it being “easier on the pipes” this makes sense.

However, there is no need to switch over to soft water if you have had kidney stones. The link between kidney stone formation and hard water remains nebulous and unfounded.

Whether you drink calcium-rich hard water or softer alternatives, the main rule remains true – hydration is paramount for prevention of kidney stones. Simply by drinking enough fluids we dilute that risk of kidney stone formation.

❔ Frequently Asked Questions

Can Hard Water Give You Kidney Stones?

No, there is no such thing as hard water kidney stones. There are a variety of risk factors that increase your risk for renal stones and hard water is not considered one. When it comes to water, the most important thing is making sure you drink enough (regardless of if it is soft or hard water). Drinking water in adequate amounts will help dilute your urine and prevent the crystal forming substances from crystallizing.

What Type of Water is Best for Kidney Stones?

Whether you prefer hard or soft water, it doesn’t matter! The most important thing is that you drink plenty of water each day. Aim for at least 8 to 10 cups per day. If you’re a heavy sweater, live in a hot climate or exercise frequently, you may need more.

Does a Water Filter Help with Kidney Stones?

No, a water filter will not help with kidney stones. There is no research to support this. If you have had kidney stones, make sure you bring in a kidney stone so your doctor can identify the type of kidney stone you may be having. After that, make an appointment with a Registered Dietitian to review specific changes you can make to your diet to prevent kidney stone recurrence.

  • Roxanne Trotter
    MS, RDN

    Registered Dietitian Roxy, fueled by her love for food and wellness, tackles misinformation head-on. Her Master's in Human Nutrition and diverse experience (weight management, hospitals) equip her to translate complex health topics, especially those related to water quality. Through her own practice (Nutremedies LLC) and writing for Water Filter Guru, Roxy empowers readers with accurate, evidence-based information, helping them make informed choices for a healthier life, one sip at a time.

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