What Is Alkaline Water?

Medically Reviewed by Zilpah Sheikh, MD on September 25, 2023
3 min read

Water is important to every cell, tissue, and organ in your body. The best way to stay hydrated: glug-glug-glug glasses of water throughout the day.

But which kind of water? Some people claim that alkaline water is better than anything you could get from the tap. But the science isn't there to back it up.

Water is a combination of hydrogen and oxygen. That's why you call it H2O. Water’s pH level determines how acidic it is and ranges from 0 to 14. A pH of 7 is considered neutral. That “seven” number is considered neutral or balanced between acidic and alkaline. If water is below 7 on the pH scale, it's "acidic." If it's higher than 7, it's "alkaline."

EPA guidelines state that the pH of tap water should be between 6.5 and 8.5. Still, tap water in the U.S. tends to fall below that -- in the 4.3 to 5.3 range -- depending on where you live.

Bottled water falls under different standards depending on whether it claims to be alkaline. Bottled alkaline water has a pH level above 7. In some cases, manufacturers use a special device to change the chemical makeup of the water. Other times, they add nutrients to the water to change its pH.

For comparison, orange juice has a pH of 3.3 and black coffee is about a 5. Pure water has a neutral pH of 7. But tap water in the U.S. tends to fall below that -- in the 4.3 to 5.3 range -- depending on where you live.

Alkaline water enthusiasts claim that its increased hydrogen provides greater hydration than regular water, especially after a hard workout.

Fans of the stuff also say that regular drinking water with a pH below 7 creates too much acid in your blood and cells. They blame plain water's low pH for all sorts of health problems, from osteoporosis to cancer.

Water that is more alkaline supposedly reduces acid in the bloodstream and:

  • Improves metabolism
  • Increases energy
  • Slows aging
  • Improves digestion
  • Reduces bone loss

Backers of high-pH water say it also has the power to starve cancer cells.

The health claims about alkaline water are more about sales than science. There isn't much research to support them.

Also, your body, on its own, can keep your pH levels at an even keel. Your kidneys are your built-in filtration system. It's their job to balance the acid levels in your body. If your blood gets too acidic, your body brings it down by breathing out more carbon dioxide.

Your stomach is the great equalizer. Your gastric juices -- a combination of digestive enzymes and hydrochloric acid -- neutralize everything you eat and drink. Basically, your stomach will re-acidify alkaline water before it can do anything the health claims promise.

Alkaline water may taste bitter or different from your tap water. This can also change the taste of anything you use it in, like coffee or tea.

Unless you have a kidney disease, alkaline water doesn't pose any serious health risks. The high pH could make your skin dry and itchy or cause an upset stomach, but that's about all.

Just because it's safe, though, doesn't mean it does anything for you. For all the benefits of a tall glass of water, fill up at the tap.