Hard Water and Kidney Stones


Astonishingly, kidney stones have been linked to hard water since the early 1990’s. There is an assumption that calcium is the major material in hard water that contributes to kidney stone formation. It is known that factors such as diet, genetics, and exercise also influence the formation of kidney stones. Kidney stones can cause skin and hair problems, and there have been various devices introduced to soften water. Additionally, plastic test strips can be used to test water quality.

What is Hard Water?

Hard water is water that contains calcium and magnesium salts, mainly chlorides, sulphates, and bicarbonates. Bicarbonate converts to insoluble carbonate after boiling; therefore, calcium carbonate tends to cause temporary water hardness.

Calcium and Limescale

The evaporation of hard water causes a calcium and magnesium substance called limescale. Apparatus with heating elements, like broilers or heat exchangers, have more accumulation of these deposits, which can also be found on equipment like washing machines and dishwashers.

Causes of kidney stones

Hard deposits made up of minerals and salts formed inside the kidneys are known as kidney stones. Kidney stones can also sometimes be called renal calculi, nephrolithiasis or urolithiasis. Any part of a urinary tract (kidney to the urinary bladder) can be affected by kidney stones. When the minerals crystallise and stick together the concentration of urine becomes high, leading to stone formation

Different types of kidney stones are; calcium oxalate, cystine, struvite and uric acid. There are different treatments that can treat kidney stones ,such as shockwave lithotripsy, ureteroscopy, percutaneous nephrolithotomy or nephrolithotripsy. 

People suffering from kidney stones may have one or more symptoms i.e. feelings of nausea, vomiting, and severe pain in the lower back.  Urine will have a bad smell or will appear cloudy, and there may be traces of blood. If the urine is highly concentrated with minerals, calcium, and uric acid substances, they are likely to form crystals which tend to stick together resulting in kidney stones. This happens due to the low volume of fluid and supplementary constituents in the urine. If the kidney stone is very small, like a grain of sand, then it can be passed through urine, but when it is large it can block the flow of urine and is very painful.  

The Relationship between Hard Water and Kidney Stones

There is not much evidence of hard water contributing to kidney stones. Studies were conducted on people who live in areas where hard water is supplied, and it was found that kidney stones were not likely to be caused by hard water for most people. 

Drinking hard water results in a rise in urine calcium, and a high level of calcium is a risk factor for kidney stones, but if people don’t have a history of kidney stones it is unlikely this will lead to them developing them. 

People who had kidney stones in the past and have a high content of calcium in the urine are most likely to develop kidney stones. Therefore, it is important to check the amount of calcium present in the tap water. The volume of calcium in the urine may increase if there is a high intake of hard water. Hence, having a low sodium and sugar diet with plenty of vegetables and fruit and drinking lots of fluids is advised. 

According to the research, an approximate hardness level of 5mmol/l,  and mineral rich hard water with TDS (total dissolved solids) of above 400 ppm (parts per million) have been found to increase the risk of kidney stones.

Research on Hard Water and Kidney Stones

Various studies have been conducted in several parts of the world. In West Benga,l there was no link found between hard water quality and kidney stone disease1. Another study showed that hard water is supportive for calcium stone formers as a high level of calcium can lead to hypercalciuria and stone formation is also impacted by other aspects. There is a varied amount of minerals present in water, but high magnesium and bicarbonate content is suggested for patients suffering from kidney stones2. Hypocitraturia and hypercalciuria are contributors to kidney stone formation. 

Dietary advice to decrease the sodium intake to 2300 mg and protein to 0.8-1g per kg of body weight per day, and calcium intake through foods, is given. In some cases, medications are also advised. Additionally, therapy is suggested with a thiazide-type diuretic like 25 mg of chlorthalidone every day to reduce the amount of calcium in the urine. Follow-up is recommended to monitor the patients.3  

Health Risks of Limescale and Hard Water 

There are no serious health problems related to hard water intake but hard water can contribute to skin and hair related issues. Children may suffer from eczema.  Minerals present in hard water are known to alter the pH balance of the skin. People may suffer from dry skin as a result of the interaction of soap and the minerals present in hard water. Since less lather is formed with hard water, there is the possibility of traces left on the skin, which can disrupt the skin barrier, block pores, and lead to dryness and breakouts. It can also leave hair dull, frizzy, and brittle since the hair strands get damaged. Hair loss and itchy scalp are the main issues reported by patients.

Treatment for Hard Water and Limescale

  • Cleaning limescale from equipment with mild acidic substances like lemon juice or vinegar are the easiest forms of treatment. A cleaning paste of baking soda and undiluted white vinegar can be used for stubborn stains. Devices like Scalewatcher are a permanent solution, as it is a device which softens the water. Carbon water filters can also be used. 

Test Strips

Plastic test strips have chemically impregnated pads at the end. The pads tend to react with specific ions and result in a specific colour. This colour is matched with the closest printed colour on a standard chart and relate to several different concentrations. This helps in determining the concentration of hardness  in the water. The standard value of the strip is 0-1000 ppm or 0-59 grains of hardness.


Kidney stones are not a serious issue if identified early, but if calcium levels increase in the urine, it can cause problems in the body leading to the formulation of kidney stones, and surgical treatments may be needed. Intake of hard water has no identified link to the formation of kidney stones, but more research is needed in this area to confirm the association of hard water and kidney stones.

FAQs Section

Related questions asked on Google:

  • Can calcium in water cause kidney stones
  • Does hard water cause calcium deposits
  • Are kidney stones a build up of calcium
  • Does hard water affect kidney
  • Does hard water give you kidney stones
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

Get our health newsletter

Get daily health and wellness advice from our medical team.
Your privacy is important to us. Any information you provide to this website may be placed by us on our servers. If you do not agree do not provide the information.

Samriti Juneja

Masters of Science in Human Nutrition, University of Aberdeen, Scotland, UK
Researched about to carry out the tissue analysis of metabolic tissues from the GPR75 knockout mice to identify the changes in gene expression, protein expression and histology. Furthermore, observing its relationship with obesity.

Leave a Reply

Your email address will not be published. Required fields are marked *

my.klarity.health presents all health information in line with our terms and conditions. It is essential to understand that the medical information available on our platform is not intended to substitute the relationship between a patient and their physician or doctor, as well as any medical guidance they offer. Always consult with a healthcare professional before making any decisions based on the information found on our website.
Klarity is a citizen-centric health data management platform that enables citizens to securely access, control and share their own health data. Klarity Health Library aims to provide clear and evidence-based health and wellness related informative articles. 
Klarity / Managed Self Ltd
Alum House
5 Alum Chine Road
Westbourne Bournemouth BH4 8DT
VAT Number: 362 5758 74
Company Number: 10696687

Phone Number:

 +44 20 3239 9818