By Christopher Bergland 

 Medically reviewed by Jamie Johnson, RDN

Alkaline water is slightly less acidic than regular tap water, which some people believe offers health benefits. In theory, alkaline water can alter the pH balance of the body, making it less acidic and more basic (alkaline). By doing so, it is thought to do everything from alleviating acid reflux and promoting weight loss to treating liver disease and preventing cancer.

This article looks at whether alkaline water lives up to the health claims and if there are actual benefits and risks to drinking this increasingly popular grocery store item.

What Is Alkaline Water?

In chemistry, pH stands for "potential of hydrogen." The concentration of hydrogen ions in a liquid determines whether it is acidic or alkaline (also known as basic).

The pH values of solutions are based on a scale of 0 to 14, with 7.0 being neutral or pH balanced. Anything under 7.0 is considered acidic, and anything over 7.0 is considered alkaline or basic.

The concentration of hydrogen ions in a solution is inversely related to a solution's pH. What this means is that the higher the concentration of hydrogen ions, the lower the pH (making the solution more acidic). On the flip side, the lower the concentration of hydrogen ions, the higher the pH (making the solution more alkaline).

Alkaline water found on grocery store shelves has a pH of roughly 8.0 to 9.0. In contrast, regular bottled water will have a pH of around 6.5 to 7.5.1 (By way of reference, human saliva is slightly acidic with a pH of between 6.3 to 6.7.)2

As small as these differences may seem, they do alter water in some noticeable way. Alkalinity tends to create a smoother, slightly sweet taste with a "slippery" or "velvety" texture on the tongue compared to distilled water.

Too Acid or Too Alkaline?

Hydrochloric acid (HCl) used for industrial cleaning has a pH of 0, while sodium hydroxide (NaOH) used in explosives has a pH of 14. Neither is fit for human consumption.

How Alkaline Water Is Made

There is water in nature that is alkaline. Such is the case with spring water wherein the passing of water through rocks causes it to lose hydrogen ions. This happens because the movement of hydrogen through certain minerals causes it to become electrically charged; in the process, the positively charged ion is shed and the water becomes more alkaline.

The same principle—called ionization—is used to make bottled alkaline water. In commercial production, water is passed through an ionizer using powerful electromagnets to separate hydrogen ions from a salt acid called carbonate which "holds" hydrogen in water. By breaking the bond, hydrogen ions are released, making the water more alkaline.3

Because of this process, alkaline water is sometimes referred to as "electrolyzed-reduced water."3

In addition to buying bottled alkaline water, consumers can buy home ionizing units online or in big box stores to make their own alkaline water.

Benefits of Alkaline Water

Some alternative health practitioners believe that alkaline water offers health benefits by changing the alkalinity of the body and reducing the harm that acids can do to cells and tissue.

While the overarching rationale may seem sound—since high acid in the stomach and blood can cause health problems—there is no evidence that drinking alkaline water can change the pH balance in the body. The only exception may be in the stomach, but even that effect is short-lasting.

This is because the pH of the body is largely regulated by the kidneys which are tasked with filtering and removing excess acids and alkaline from body fluids. Once acid or alkaline levels build up excessively, a part of the brain called the hippocampus will tell the kidneys to remove them in an ongoing effort to maintain homeostasis (equilibrium) in the body.4

Claims that alkaline water can increase longevity, improve liver function, treat diabetes, or prevent cancer remain unproven. With that said, there may be certain benefits to drinking alkaline water based on the current body of research.

Gastrointestinal Reflux Disease (GERD)

According to an older study from researchers at the New York Medical College, alkaline water may have therapeutic benefits for people with gastroesophageal reflux disease (GERD).5

The researchers found that consuming pH 8.8 alkaline water denatures (takes away) a digestive enzyme called pepsin, which seems to alleviate acid reflux symptoms. They also found that alkaline water with 8.8 pH levels had good acid-buffering qualities.

A subsequent study from New York Medical College published in 2017 found that a diet comprised of alkaline water and a plant-based Mediterranean diet was as effective in controlling acid reflux as acid-reducing proton pump inhibitor (PPI) drugs, suggesting an alternative approach to treatment.6

Even so, it is unclear if the diet, the water, or both contributed to the results.

Weight Loss

Alkaline water is thought by some to promote weight loss, though it is unclear how it is meant to do so. Some proponents have suggested that it does so by evading the effects of fasting-induced acidosis. This is the natural rise in blood acid during periods when you are not eating.7

While it is known that metabolic acidosis can cause weight gain along with heart palpitations and other symptoms, it is not an everyday occurrence or a major cause of weight gain or obesity. Rather, it is more often seen in the context of chronic kidney disease (CKD).8

Even so, a 2022 study from Malaysia reported the consumption of at least 1 liter (roughly 4 cups) of alkaline water per day for at least two months led to marginal reductions in blood sugar, cholesterol, triglycerides, blood pressure, and waist circumference (but not weight) in 148 postmenopausal females compared to counterparts who drank only regular tap water.9

More research is needed.

Risks and Side Effects of Alkaline Water

Drinking slightly alkaline water (pH 7.0 to 8.5) is considered safe and shouldn't have any adverse side effects.10

However, consuming copious amounts of highly alkaline water (pH 9.0–10) may affect digestion and give you an upset stomach. This is because very alkaline water can decrease gastric acids in the stomach, leading to bloating, belching, or feeling full quickly or for long periods after eating.11

Although some people suggest that alkaline water may cause kidney stones as it is rich in alkalizing minerals such as calcium, potassium, and bicarbonate, there is little evidence that it poses any such risk.12

How to Make Alkaline Water

The easiest and least expensive way to make alkaline water is to add a pinch of baking soda to a glass of tap water. Baking soda (sodium bicarbonate) has a pH of about 9.0.

Although adding baking soda to water boosts its alkalinity, consuming excess sodium bicarbonate may affect electrolyte levels and lead to negative health consequences, including hypokalemia (low blood potassium), hypernatremia (high blood sodium), or worsening chronic kidney disease.13

Alkalizing fruits and vegetables can also be added to tap water to make it more alkaline. An easy way to do this is to add slivers of cucumber to a pitcher of water and let it soak in the fridge for a few hours.

There are also factory-made filters and ionizer machines that make alkaline water. But before investing in an expensive gadget, buy an inexpensive pH water test at your hardware store to check your tap water's pH level.

What Is the pH of Tap Water?

The U.S. Environmental Protection Agency (EPA) requires public water systems to maintain pH levels of 6.5 to 8.5.10 This means that in some parts of the United, the water supply may be naturally alkaline.

In parts of the U.S., well water can be abnormally acidic and may benefit from being alkalized. If your house doesn't get water from an EPA-regulated public water supply, spending money to keep your water supply at healthy pH levels is probably a worthwhile investment.

Summary

Alkaline water is water with a pH value greater than 7.0. Most commercial brands of alkaline water have pH levels between 8.0 and 9.0. Although proponents suggest that drinking alkaline water may help certain health conditions, the evidence supporting the claims is generally weak.

Sources

ETR Laboratories. Different pH values of drinking water.

Baliga S, Muglikar S, Kale R. Salivary pH: a diagnostic biomarker. J Indian Soc Periodontol. 2013 Jul-Aug;17(4):461–465. doi:10.4103/0972-124X.118317

LeBaron TW, Sharpe R, Ohno K. Electrolyzed–reduced water: review II: safety concerns and effectiveness as a source of hydrogen water. Int J Mol Sci. 2022 Dec;23(23):14508. doi:10.3390/ijms232314508

Ruffin VA, Salameh AI, Boron WF, Parker MD. Intracellular pH regulation by acid-base transporters in mammalian neurons. Front Physiol. 2014;5:43. doi:10.3389/fphys.2014.00043

Koufman JA, Johnston N. Potential benefits of pH 8.8 alkaline drinking water as an adjunct in the treatment of reflux disease. Ann Otol Rhinol Laryngol. 2012 Jul;121(7):431-4. doi:10.1177/000348941212100702

Zalvan CH, Hu S, Greenberg B, Geliebter J. A comparison of alkaline water and Mediterranean Diet vs proton pump inhibition for treatment of laryngopharyngeal reflux. JAMA Otolaryngol Head Neck Surg. 2017 Oct;143(10):1023–1029. doi:10.1001/jamaoto.2017.1454

Hottenrott K, Werner T, Hottenrott L, Meyer TP, Vorman J. Exercise training, intermittent fasting and alkaline supplementation as an effective strategy for body weight loss: a 12-week placebo-controlled double-blind intervention with overweight subjects. Life (Basel). 2020 May;10(5):74. doi:10.3390/life10050074

Navaneethan SD, Shao J, Buysse J, Bushinsky DA. Effects of treatment of metabolic acidosis in CKD: a systematic review and meta-analysis. Clin J Am Soc Nephrol. 2019;14(7):1011-1020. doi:10.2215/CJN.13091118

Chan YM, Shariff ZM, Chin YS, Ghazali SS, Associations of alkaline water with metabolic risks, sleep quality, muscle strength: a cross-sectional study among postmenopausal women. PLoS One. 2022;17(10):e0275640. doi:10.1371/journal.pone.0275640

U.S. Environmental Protection Agency. Drinking water regulations and contaminants.

Fujimori S. Gastric acid level of humans must decrease in the future. WJG. 2020;26(43):6706-6709. doi:10.3748/wjg.v26.i43.6706

Liu L, Lin Ch, Li X, et al. Protective effect of alkaline mineral water on calcium oxalate-induced kidney injury in mice. Evid Based Complement Alternat Med. 2023;2023:4559802. doi:10.1155/2023/4559802

Yehia HMAS, Said SM. Drinking water treatment: pH adjustment using natural physical field. JBM. 2021;09(06):55-66. doi:10.4236/jbm.2021.96005

Additional Reading

Kulthanan K, Nuchkull P, Varothai S. The pH of water from various sources: an overview for recommendation for patients with atopic dermatitis. Asia Pacific Allergy. 2013;3(3):155-160. doi:10.5415/apallergy.2013.3.3.155

United States Geological Survey (USGS). pH Scale.

By Christopher Bergland
Christopher Bergland is a retired ultra-endurance athlete turned medical writer and science reporter.