You might have heard that hard water is bad for your kidneys or could cause kidney stones. Is this true? Should you avoid drinking hard water for this reason? How can you reduce your risk of kidney stones from drinking tap water at home?
We’ve answered all these questions below.
📌 Key Takeaways:
- Some studies show that hard water may increase risk of kidney stones.
- There is a very low risk of calcium stone development for the average general population of healthy humans.
- If you have a history of kidney stones or you have any reason to be concerned, ask your doctor for advice on whether or not you should drink hard water.
Table of Contents
🤔 What Is Hard Water?
Hard water is water that contains excess calcium and magnesium.
These minerals combined form limescale, a white, chalky substance also known as scale buildup, which can be found on our faucets and shower heads, and in our pipes, coffee machines, tea kettles, water heaters, and other appliances and fixtures.
Most homes in the US have hard water. Your local water treatment plant won’t remove hardness minerals from your water because they don’t have any known health concerns – and, in fact, they’re needed by the human body for many processes.
Many bottled water products, including natural spring water, contain more calcium than the average tap water supply.
🔎 How To Know If You Have Hard Water
You can’t draw an association between hard water and kidney stones until you know whether or not your water is hard.
There are a few ways to know if you have hard water:
- Look for signs. Hard water causes scale buildup, which is visible on your fixtures and in your appliances.
- Check your Water Quality Report. Your water supplier should test your water hardness and share their findings in your annual Water Quality Report.
- Test your water. You can buy a DIY water hardness test kit to test your tap water’s calcium content at home.
🚱 Does Hard Water Cause Kidney Stones?
Several studies, including this 1999 study, have found a link between hard water ingestion and calcium stone formation in the kidneys.
So, can hard water cause kidney stones? Potentially, yes. Urine calcium was found to be higher in people who ingested hard tap water, and high levels of calcium in the urine is a risk factor for kidney stones.
However, the evidence we have so far is limited, and studies haven’t found a definite increased incidence of kidney stones in people living in hard water areas.
There are several types of kidney stones. Calcium oxalate, which forms on the walls of the kidneys during the excretion process, is responsible for the formation of the “calcium stone”. However, too much calcium in the human body is not 100% to blame in this scenario.
Calcium stones are typically only formed when a number of risk factors are present at once, including poor hydration, high sodium intake, and even low calcium intake. Having poor health in general also increases your risk of calcium stones.
The average healthy person is unlikely to develop calcium stones as a result of drinking tap water or bottled water with a high mineral content.
👨⚕️ What Is The Likelihood That Hard Water Will Cause Kidney Stones?
It’s difficult to say for certain how at risk you are of developing kidney stones from drinking hard water.
This depends on factors including:
- Your predisposition to kidney stones – Some people are simply more at risk of kidney stones than others.
- Environmental factors – Living in warm, dry climates also increases the risk of kidney stone formation.
- Your water hardness – Drinking very hard water with excess calcium puts you more at risk than drinking soft water with no minerals.
- Your hard water consumption – If you drink large quantities of mineral-rich water daily, there’s a chance that you’re more at risk of calcium stone formation than if you drink only small amounts of high-mineral water, alongside adequate consumption of low-mineral water, per day.
- Your diet – The calcium carbonate you get from your diet as a whole, as well as the amount of protein, sodium, and sugar you eat, will also affect your likelihood of developing kidney stones.
- Certain health conditions – Diabetes, obesity, and high blood pressure all increase your risk of developing kidney stones.
For most people, drinking even very hard water is unlikely to actually cause kidney stones because our bodies are programmed to break down certain chemicals to prevent kidney stone formation, regardless of our calcium intake.
But are you at an increased risk of kidney stones if you drink hard water? According to some studies, potentially.
🩺 How To Reduce The Risk Of Kidney Stones From Hard Water
If you’re at risk of kidney stones or you just want to avoid this health condition, here are a few ways to reduce the association between your drinking water habits and calcium stone formation.
Drink Plenty Of Water
The best way to avoid kidney stones is to simply drink plenty of water and stay hydrated – whether that water is hard or soft.
Drinking extra water dilutes the substances that cause stones to form. So, make sure you’re drinking at least 2 liters of water (not including sodas, coffees, or fruit juices) per day, and your chances of developing calcium stones are minimal.
On the subject of beverage intake, citrus beverages like orange juice and lemonade are thought to reduce the potential for stone development in the kidneys, so you can’t go wrong if you drink a glass of OJ with your breakfast.
Assess Your Dietary Calcium Intake & Avoid Calcium Supplements
An increased overall calcium dietary intake is associated with kidney stones – so that applies to the calcium you get from all your foods as well as your tap water.
So, if you know you’re getting a lot of calcium from your hard water, consider reducing the calcium in your diet and cutting out your calcium supplements (if you take them). You should only do this if you know for certain that you’re putting your health at risk by consuming too much calcium in your diet.
We do not recommend reducing your dietary calcium intake without consulting a doctor. Since hard water only contributes minimally to your overall calcium consumption, reducing or eliminating foods containing healthy minerals in your diet might actually have detrimental effects and lead to deficiencies.
Install A Water Softener
The simplest way to prevent your tap water from causing kidney stones is to eliminate the water hardness minerals from this water supply.
A water softener is the best solution to hard water. This system is installed at your home’s main water line and exchanges dissolved calcium and magnesium ions with sodium. The soft water that leaves the system is calcium and magnesium-free.
If you choose to remove the hardness minerals from your drinking water, it’s important to make sure you still get plenty of essential nutrients from the foods you eat. Speak to your doctor if you’re unsure about what you should be eating or you need advice about your calcium intake.
Note: since sodium is another mineral that’s associated with kidney stones, you might be concerned about adding it to your water in a salt softener. However, even for very hard water, only very small amounts of sodium are added. Drinking this water all day will contribute to around 20-30% of your dietary intake of sodium at most.
You could always substitute sodium for potassium in your water softener if you want to completely avoid the potential health effects of salt in your water.
📑 Final Word
Will hard water cause kidney stones in the average healthy person? It’s unlikely.
Even if a couple of studies have found that drinking water with a high mineral content may increase calcium in the urine, there hasn’t been any research demonstrating that a larger percentage of people living in hard water areas develop kidney stones compared to people living in soft water areas.
So, you should be able to safely drink tap water containing calcium and magnesium without having to worry about developing calcium stones.
Most people choose to install water softeners because salt softeners prevent mineral deposits in their pipes and appliances – not so that they can avoid kidney stones.
But if you are concerned for any reason, your doctor can provide personal advice that’s unique to your situation and your medical history.