What is pH?

You may have heard the word “pH” used to describe drinking water quality, but do you know what it means?

pH is a measurement of electrically charged particles in a substance. It indicates how acidic or alkaline (basic) that substance is. The pH scale ranges from 0 to 14:

  • Acidic water has a pH lower than 7. The most acidic substances have a pH of 0. Battery acid falls into this category.
  • Alkaline water has a pH of 8 or above. The most alkaline substances, such as lye, have a pH of 14.
  • Pure water has a pH of 7 and is considered “neutral” because it has neither acidic nor basic qualities.

What pH is safe for drinking water?

The is in charge of monitoring public drinking water quality across the United States.

pH isn’t a quality that falls under EPA regulation because it’s considered an aesthetic quality of water. However, the agency recommends that municipal drinking water suppliers keep their water supply at a pH of 6.5 to 8.5.

What does a changing or unsafe pH mean?

Freshwater pH varies across the world depending on weather patterns, human activity, and natural processes.

Water with a very low or high pH can be a sign of chemical or heavy metal pollution.

Water that doesn’t fall in the “safe” pH range of 6.5 to 8.5, particularly if it’s alkaline, isn’t necessarily unsafe. However, very alkaline water can have an unpleasant smell or taste, and it can also damage pipes and water-carrying appliances.

Acidic water with a pH of less than 6.5 is more likely to be contaminated with pollutants, making it unsafe to drink. It can also corrode (dissolve) metal pipes.

Many municipal water suppliers voluntarily test the pH of their water to monitor for pollutants, which may be indicated by a changing pH. When pollutants are present, water companies treat their water to make it safe to drink again.

Common water pH levels

Type of waterpH level
Tap waterVaries; typically about 7.5
Distilled reverse osmosis water5 to 7
Common bottled waters6.5 to 7.5
Bottled waters labeled as alkaline8 to 9
Ocean waterAbout 8
Acid rain5 to 5.5

Alkaline water: A new trend

Alkaline water has become a popular drinking water choice over the past few years. Some people say that drinking slightly alkaline water — with a pH between 8 and 9 — can improve your health. They say it may make you age more slowly, maintain a healthy pH in your body, and block chronic disease like cancer.

Despite the many health claims made by alkaline water drinkers and sellers, there’s little to any scientific evidence that alkaline water is healthier than other kinds of drinking water.

But there are a few studies suggesting alkaline water may benefit the health of people with certain medical conditions, such as:

  • acid reflux ()
  • high blood pressure, diabetes, and high cholesterol ()

High alkaline, electrolyzed water may also be helpful after .

More research is needed to fully support the findings of these small studies.

Testing pH at home

Municipal water suppliers normally do a good job of keeping their water at a normal pH of around 7, so there’s usually no need to do your own home testing.

But if you notice that your faucets and pipes have taken on a rusty red, white, or blue color, you might want to take steps on your own. This discoloration — as well as any discoloration of your drinking water — is a sign of corrosion caused by acidic water. Corroded pipes should be inspected by a professional plumber and replaced if necessary.

It’s fairly easy and inexpensive to test the pH of your drinking water at home. All you need is a home test kit. These come in many different forms at different price points.

Some of the most highly rated pH test products are water quality tester “pens.” Simply dip the pen into a sample of your drinking water and a few moments later receive an accurate pH reading. Two popular models are the and digital water meters.

If your water falls within the EPA recommended range of 6.5 to 8.5, there’s no need to take action.

The takeaway

If your drinking water pH falls outside of the safe range, it’s time to act. Call your local drinking water company to alert them to your test findings.

They may visit your residence to professionally test your water. They should handle the situation if their test also comes back abnormal. Since pH is often a sign of contamination, the water company may run several tests looking for various contaminants.

In the meantime, if you suspect problems with your drinking water — whether it’s pH, a strange texture, a bad taste, or a bad smell — you can purchase a pitcher like the one made by or install a filter system in your kitchen sink. has a popular filter system.

Be sure to keep in communication with your local water provider. Ask for an annual report to stay on top of your drinking water quality.

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