Which factor primarily affects the corrosiveness of water?

The corrosiveness of water is significantly influenced by its pH levels. Water with a low pH (acidic) tends to be more corrosive, as it can more readily react with metals and other materials, leading to deterioration or leaching. This can result in increased metal ions in the water supply, which may compromise water quality and affect human health.

In addition, while other factors such as water temperature or the presence of oxygen can contribute to the overall corrosiveness, they do not play as central a role as pH. For example, oxygen can facilitate rusting in metals but is not a primary driver of corrosion on its own. The overall dissolved solids contribute to the water's chemical composition but are not definitive in establishing corrosiveness without considering the pH levels. Thus, the control of pH is a critical aspect of water treatment processes to manage corrosion and protect both infrastructure and consumer health.