Difference Between Acidity and Alkalinity of Water l Acidity vs Alkalinity of Water

The key difference between acidity and alkalinity of water is that the acidity of water is the water’s ability to neutralize a base whereas the alkalinity of water determines water’s ability to neutralize an acid.

We can name acidity of water as the “base neutralizing capacity” and alkalinity of water as the “acid neutralizing capacity”. We can determine these two parameters using laboratory experiments. It is very helpful in determining the water quality and the degree of water pollution.


1. Overview and Key Difference
2. What is Acidity of Water
3. What is Alkalinity of Water
4. Side by Side Comparison – Acidity vs Alkalinity of Water in Tabular Form
5. Summary

What is Acidity of Water?

Acidity of water is the ability of water to neutralize a base. We can name it as the base neutralizing capacity of water. It also gives how much of a standard base that we need to add to water in order to raise the pH of water to a specific value. The major basic chemical species in water are hydroxide ions. Hence, the term acidity can also be given as the water’s capacity to neutralize hydroxide ions, though it is not very accurate because there can be some other basic chemical species as well.

The acidity of water arises due to the dissolution of mineral acids such as sulfuric acid and hydrochloric acid. Or else, the acidity of water can be a result of the dissolution of carbon dioxide gas. In drinking water sources, carbon dioxide is the major contributor to the acidity of water. If water has high acidity, the corrosiveness of water is also high. Therefore, it can harm water pipes made of copper. Hence, high levels of copper and lead may exist in acidic drinking water.