pH Values of Water with ph Level Chart – A Detailed Explanation

Lab testing at home

You may have heard the term ‘pH values of water’ used when talking about the quality of water. But what does it really mean?

Here, we have a detailed and complete explanation of what pH values of water mean, and what you need to understand. It will help you determine whether or not the water you use at home has any factors that may adversely affect you.

In simple terms, pH is a measure of how acidic or basic your water is. pH stands for the power of hydrogen. So what pH actually measures is the relative amount of free hydrogen and hydroxyl ions that are present in your water. It is measured on a scale that ranges from 0 to 14.

This scale can be divided into three categories.

Three Categories of pH Value of Water

1. Acidic Water

Acidic water is any water with a pH value lower than 7, with 0 being the most acidic. Acidic water is mainly soft and corrosive. Strong acids, such as hydrochloric acids (HCl) have a pH of 0.

Acidic water can cause damage to metal pipings and tend to have a metallic or sour taste to them. They can also cause a lot of health damages. Not just this, but they can stain your sinks and laundry.

2. Alkaline Water

Alkaline, also known as basic, water is any water with a pH of 8 or more. In this scale, 14 represents the most alkaline such as sodium hydroxide (NaOH). Basic water is synonymous with hard water.

While the health risks from this are minimal, the main problem with it is scaling. It can add a bitter taste to your drinking water and cause scale deposits on your dishes, showers, and drains. It also reduces the effectiveness of soap and detergent.

3. Pure or Neutral water

Pure water is water that has a pH of 7. This is also considered neutral as it is neither acidic nor basic. However, the ideal drinking water for humans can be anywhere between 6-8.5.

Why is pH Value Important?

The pH value of any substance is affected by the chemicals present in water. Similarly, it can also determine the solubility of water and the number of nutrients available in it for aquatic life. A change in pH value can thus be an indicator of pollution or any sudden change that you should be aware of.

Similarly, atmospheric gases, as well as temperature, can affect the pH value of any water. Water with widely fluctuating pH values can be an indicator of chemical or heavy metal contamination. This is why pH value can be an important indicator of the chemical changes in any water.

Different pH Levels of Typical Materials

The following table will help you better understand the pH values of the different types of water you use in your day to day life. This will also help you know about the water you use to drink or wash your dishes.

Source: Khan Academy
Water pH value
Acid rain 5-5.5
Normal rainfall 5.6
Distilled water after reverse osmosis 5-7
Tap water Approx. 7.5
Sea Water 8
Alkaline bottled water 8-9
Bottled water 8-9

Similarly, the following is a list of other substances and their pH values. These are items you use on a near-daily basis. The following table can help you get a clear understanding of the range of pH values.

Substance pH value
Lemon juice 2
Apple Juice 3
Coffee 5.5
Milk 6.2
Blood 7.4
Baking soda 9.5
Bleaches, oven cleaner 13.5
Liquid drain cleaner 14

Factors That Influence the pH of Water

By now, we have understood that the pH value is vital in understanding the water you use. However, this value is not constant. This means that it can be affected by multiple factors, both environmental and man-made. Some of these are listed as follows:

1. Carbon Dioxide

Carbon dioxide is one of the most common reasons that water turns acidic. Many natural processes, such as photosynthesis, respiration, as well as decomposition, cause a rise in the level of carbon dioxide. It can then react with water to form carbonic acid. This can cause an imbalance in pure water. Thus, as the carbon dioxide levels rise globally, a change in the pH values can be seen in the oceans across the world over time.

2. Natural Influence

Limestone and carbonate materials can also cause fluctuations in the pH values of water. Both these materials react with hydrogen and hydroxyl ions that usually cause water to neutralize. In case of additional exposure, it can cause the water to become slightly more basic.

Similarly, natural precipitation can also lower the pH of water. Pine or fir needles act similarly. They reduce the pH of the surrounding soil so that any water that runs over it experiences a reduced pH.

3. Human Influences

The changes caused by human influences are primarily related to pollution. One of the primary examples is acid rain. Acid rain refers to rain with a pH value of less than 5, caused due to the reaction of water with acidic compounds such as nitrogen oxide, sulfur oxide, and others.

The increasing carbon dioxide discussed previously also falls under human influences. Similarly, pollution like wastewater, industrial wastes can cause an imbalance in the ecosystem. This can affect nearby water sources and even the surrounding soil.

How to Test pH Values at Home?

The first thing we need to do before testing pH is to understand how pH values are reported. They are denoted in logarithmic units, which means that every number represents a change that is 10-times more than the last.

For instance: water with a pH of three is ten times more acidic than water having a pH of four. We don’t need complicated machinery to find out how acidic or basic our water is. We can conduct this test ourselves with something called the Litmus Test.

1. The Litmus Test

You may have done this test in your science class. It is a simple test that can let you know whether the water you are using is acidic or basic. Litmus is a mixture of organic compounds made from lichen. It is an excellent acid-base indicator.

It turns red if the water is too acidic and blue if it is too basic. It remains neutral if the pH is at 7. You can find these litmus papers at most pet-supply stores as they are used to check the pH value of aquariums.

2. pH meter

There are also many water quality tester pens now available in the market. You will simply need to dip this pen into the sample that you want to test. Usually, you need to calibrate the pen by immersing it in a liquid with a known pH, such as pure water.

The calibration will give out a very accurate reading of the pH value of your water. As long as the sample has a pH between 6.5 to 8.5, the sample should be safe for your usage.


We must now have a much better understanding of what pH values actually represent. They are simply a measure of how acidic, basic or neutral your water sample is, and can be affected by many factors, both man-made and environmental. Since they are so easy to influence, it is always handy to know how to measure these values.