Which of the following is a common sign of water contamination in pools?

Increased chemical odor in pools is a common sign of water contamination. This phenomenon often occurs when there is an imbalance of chemicals in the water, typically due to the high presence of organic contaminants such as sweat, urine, and other impurities. When these contaminants mix with disinfectants like chlorine, they can create chloramines, which are responsible for the strong chemical smell. A heightened odor can indicate that the chemicals are not effectively treating the water or that there is a need for more frequent monitoring and maintenance.

In contrast, clear water indicates proper sanitation and filtration, balanced pH levels suggest that the water chemistry is stable, and low bacterial counts reflect good hygienic conditions. Therefore, the presence of an increased chemical odor serves as a clear warning sign that immediate attention to water quality is needed to ensure the safety and comfort of pool users.