What is the principal cause of corrosion of metals in water?

The principal cause of corrosion of metals in water is dissolved oxygen. When water contains dissolved oxygen, it can initiate electrochemical reactions that lead to the oxidation of the metal surfaces. This process is particularly significant because the presence of oxygen can accelerate the breakdown of metal structures, such as pipes and tanks, which may eventually contribute to leaks or failures in a water distribution system.

The reaction occurs because oxygen reacts with the metal, often in the presence of water and other ions, to form oxides. This phenomenon is a fundamental aspect of corrosion, particularly in environments where water is stagnant or where oxygen concentration is higher, as it can dramatically increase corrosion rates.

While pH levels, temperature fluctuations, and mineral deposits can influence the rate of corrosion or contribute to corrosion in specific contexts, dissolved oxygen is the primary catalyst that initiates and drives the corrosive processes in many typical water systems. For example, high levels of dissolved oxygen in water can cause more aggressive corrosion compared to low-oxygen conditions, making effective management of these factors essential in water treatment and distribution to safeguard infrastructure.