What is pH?

March 1, 2022
What is pH?

About the author:

Brian Campbell is the founder of WaterFilterGuru.com, where he blogs about all things water quality. His passion for helping people get access to clean, safe water flows through the expert industry coverage he provides. Follow him on twitter @WF_Guru or contact him by email [email protected].

Editor's Note: A previous version of this article used alkaline water and basic water interchangeably. While all alkaline solutions are basic, not all basic solutions are alkaline. The article has been updated to correct this error.

What is pH?

A simple definition is that it measures how acidic or basic a solution is. 

A more scientific definition is that it indicates the concentration of hydrogen ions in a liquid. While a low pH indicates a higher concentration of hydrogen, a high pH indicates a lower hydrogen concentration.

For those with a background in chemistry, one can calculate the pH of any substance by using the calculation: pH = - log [H3O+]. 

This formula is not the only way to calculate water’s pH, however. This article will explain what affects it, the problems with acidic and basic water, and how to test for it in water at home. 

What Changes the pH of Water?

Water has a neutral pH of 7, which indicates that it is neither acidic or basic. The scale ranges from 0 (very acidic) to 14 (very basic). It is normal for water to have a range of between 6.5 and 8.5 on the scale. 

pH in water may fluctuate with differing environmental factors. Rainwater is naturally more acidic, and usually has a pH of around 5.65. But when this water falls through the air, it interacts with atmospheric carbon dioxide, which increases acidity and therefore decreases pH. 

Once rainwater lands on the ground, the geology of the land will affect its pH once more. When this water seeps through layers of mineral-rich rock, it will become more basic. But if it is only exposed to igneous rock, like granite, it is unlikely that its will change much at all. 

Mining discharges and wastewater can also affect it, and in wastewater it is typically neutral, but chemicals, pollutants and other contaminants in this water can cause it to become highly acidic or alkaline. 

What Effect Does it Have On Drinking Water?

The acidity or basicity of drinking water can have an effect on its makeup. While acidic water is more likely to contain metal contaminants, basic water typically has a high concentration of healthy minerals

Basic water is said to be healthier than water with a neutral reading, as it prevents acidity in the body from causing chronic illnesses. However, there’s not much scientific evidence to back up these claims so far. What we do know is that water with a slightly higher reading of 8 to 8.5 is more likely to have a higher concentration of healthy minerals and electrolytes, like calcium, potassium and magnesium, which the human body needs to survive. 

Acidic water, on the other hand, may corrode your teeth, so it is not recommended for consumption. Acid water is also more susceptible to metal leaching, so by drinking water with a low reading, one is more at risk of consuming dangerous levels of copper, lead, and similar contaminants. 

Safe Range For Drinking Water

According to the Environmental Protection Agency (EPA), water’s safe pH range spans between 6.5 and 8.5 Anything higher or lower than this, and water is not recommended for drinking. The optimum reading for drinking water is 7. 

Risks Associated With Unsafe Levels

Acidic water and basic water each pose their own specific risks. 

Some of the risks associated with acidic water include:

Increased Metals Intake

Water with a lower pH is more likely to grab onto heavy metals like copper, lead, arsenic, zinc, and chromium. Drinking acidic water puts you more at risk of consuming a higher concentration of these metals. In the long term, this may lead to dangerous conditions like toxicity and heavy metal poisoning. 

Damage to Teeth

Your overall dental health may be affected by drinking acidic water. Because water with a low pH is more corrosive, it is likely to increase the risk of decay of the tooth enamel. The tooth enamel is important to protect the inner layers of the tooth from damage and keep teeth looking white. Decayed tooth enamel is more susceptible to cavities and infections. 

Plumbing Damage

The corrosive properties of acidic water may also damage your home’s plumbing system. Over time, water with a low pH can dissolve metal pipes, causing heavy metals to leach into your water. Acidic water can also cause pipes to wear away, resulting in leaks that may be expensive to repair.  

Some of the risks of drinking basic water include: 

Lowers Stomach Acidity

Basic water may lower pH in the stomach. This could lower the stomach’s natural acid, which is needed to kill bacteria and other pathogens, preventing them from passing into the bloodstream. 

Metabolic Alkalosis

Too much basic water can result in a condition called metabolic alkalosis, which imbalances the body’s normal pH. With metabolic alkalosis, you may experience symptoms like vomiting, nausea, muscle twitching, hand tremors, and confusion. 

Poor bone health

Alkalosis (associated with basic water) has also been known to decrease the body’s free calcium, which can affect bone health. Additionally, low levels of free calcium can slow down heart rate and cause muscle spasms. 



In a laboratory setting, pH meters are typically used to give an accurate reading in water. You can buy a meter online, but they can be on the more expensive side. 

A more affordable alternative is to purchase a single-use at home pH test kit. These test kits come with strips that one can dip into a water sample. The strip will turn a certain color to indicate how acid or basic the water is. 

One can buy different testing kits that are designed to work with specific pH ranges. When dealing with particularly acidic or basic water, make sure the kit is designed to work with this pH range. This is the better option than buying a testing kit that ranges from 1 to 14, as it may be more difficult to get an accurate result based on the test strip’s color hue. 

Test strips can be handy for initially assessing water, and testing it again after treating water to increase or decrease its pH. 

In short, if using water for drinking, one should make sure it has a pH of between 6.5 and 8.5; preferably as close to 7 as possible. Any higher or lower than this, and the water is not safe to drink.

About the Author

Brian Campbell

Brian Campbell is the founder of WaterFilterGuru.com, where he blogs about all things water quality. His passion for helping people get access to clean, safe water flows through the expert industry coverage he provides. Follow him on twitter @WF_Guru or contact him by email [email protected].

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