Which of the following factors decreases water quality in a distribution system?

Turbidity is a key factor that decreases water quality in a distribution system due to its impact on both aesthetics and health. It refers to the cloudiness or haziness of water caused by large numbers of individual particles that are usually invisible to the naked eye. These particles can include sediment, organic matter, and other contaminants.

When turbidity levels are high, they can harbor harmful microorganisms and pathogens, making the water unsafe for drinking or other uses. Turbidity can also interfere with disinfection processes, as particles can shield bacteria and viruses from disinfectants like chlorine. This complicates the treatment process and may lead to inadequate water quality.

Overall, maintaining low turbidity levels is crucial for ensuring safe and high-quality drinking water, which makes it a significant concern within water distribution systems.