What can cause a water quality complaint described as "milky water"?

The presence of entrained air is the correct answer when addressing a water quality complaint described as "milky water." This condition typically occurs when small air bubbles become trapped in the water, giving it a cloudy or milky appearance. This phenomenon can happen during water treatment processes or when water is subjected to rapid changes in pressure, such as when it flows through pipes or is delivered to a tap.

When air is introduced into the water, it forms tiny bubbles that scatter light, making the water appear opaque or white. This type of water quality issue is generally harmless and often resolves itself when the water sits undisturbed, allowing the air bubbles to escape.

While high mineral content can lead to water that has a different quality issue, such as being hard or having a distinct taste, it does not typically produce a milky appearance. The presence of chemicals can result in various undesirable effects such as taste or odor issues but is not primarily associated with the cloudy or milky characteristic. Algal blooms can affect water quality significantly but typically do not cause a milky appearance; instead, they usually result in a greenish hue or floating scum on the surface.