Of all the things to consider about hydration, the health effects of pH on drinking water probably don't cross your mind. However, alkaline water has a host of supposed health benefits, from helping the body clear toxins to improving metabolism.
The Basics of pH
If you remember those blue litmus strip experiments from high school chemistry, you might recall that pH refers to how acidic or alkaline a substance is. The pH scale ranges from 0 to 14; 7 serves as true neutral, while lower numbers signify acidity and higher numbers signify alkalinity. Since tap water is prone to some variation, it's common for your drinking water to be slightly acidic or alkaline.
Acidic things have a slightly sour flavor, so some people simply prefer the taste of ionized (alkaline) water. Some commercial alkaline water is produced by the addition of minerals, such as magnesium and calcium, adding to its supposed health benefits. It's worth noting that acidic water has no such healthy reputation, so you wouldn't be alone if you're wondering about the positive and negative health effects of pH on drinking water.
Can Abnormal pH Be Dangerous?
Public water systems in the U.S. are overseen by the Environmental Protection Agency, which has a number of regulations that apply to drinking water. The pH of drinking water, however, is considered an aesthetic quality, meaning the EPA has a recommendation for the pH of drinking water — between 6.5 and 8.5 — but it's not federally enforceable.
Therefore, as far as the EPA is concerned, the health effects of pH on drinking water as it pertains to the human body do not warrant a public health concern. That said, abnormally high or low pH water — while not usually a health threat on its own — may cause indirect health effects by corroding the metal pipes through which it travels, according to the Water Research Center. It may also signify the presence of pollutants.
For these reasons, if your tap water looks or tastes strange, it's worth checking the pH levels of your water or contacting municipal authorities to make sure it isn't symptomatic of another issue.
Alkaline Water for Rehydration
One of the main uses for alkaline water is for rehydrating the body after athletic activity because of the presence of electrolytes. A November 2016 study published in the Journal of the International Society of Sports Nutrition found that electrolyzed alkaline water had a significant impact on blood viscosity, a marker of hydration, over standard purified water. That said, the study does not clarify whether it's the effect of the electrolytes or the alkalinity that caused the result.
A small February 2017 study published in Biology of Sport found "favorable changes in hydration status" among athletes who drank mineralized alkaline water after high-intensity interval exercise. These results suggest that electrolyzed alkaline water may be better for rehydrating after exercise. However, the study, while widely cited, consisted of fewer than 40 individuals.
Additionally, it's also unclear whether the alkalinity or the presence of minerals in this study caused the observed difference — making it impossible to determine for sure whether it was in fact the pH that had health effects on drinking water.
Other Benefits of Alkaline Water
Depending upon who you ask, you might hear all manner of miraculous supposed health benefits pertaining to hydrating with alkaline water. The research to back up these claims, however, is so far limited.
One July 2012 laboratory study published in the Annals of Otology, Rhinology, and Laryngology found that alkaline water was effective in deactivating pepsin, the enzyme that causes damage to the larynx and/or esophagus among those with reflux disease. Therefore, alkaline water may have "therapeutic benefits" due to its "acid-buffering capacity," though it's worth noting that this has yet to be demonstrated in a human trial.
As for any further studies speaking to the supposed detoxifying, overall health-improving quality of alkaline water, research is scant. A May 2016 study published in Evidence-Based Complementary and Alternative Medicine found positive effects on longevity in mice that were hydrated with alkaline water. However, no such health effects of pH on drinking water have yet been demonstrated in humans.
- Clemson University: "What Is pH?"
- Journal of the International Society of Sports Nutrition: "Effect of Electrolyzed High-pH Alkaline Water on Blood Viscosity in Healthy Adults"
- Biology of Sport: "The Effect of Mineral-Based Alkaline Water on Hydration Status and the Metabolic Response to Short-Term Anaerobic Exercise"
- Annals of Otology, Rhinology, and Laryngology: "Potential Benefits of pH 8.8 Alkaline Drinking Water as an Adjunct in the Treatment of Reflux Disease"
- Evidence-Based Complementary and Alternative Medicine: "Alkaline Water and Longevity: A Murine Study"
- Water Research Center: "The pH of Water"