Which of the following may indicate well contamination?

Changes in water color, taste, or odor are important indicators of potential well contamination. When a well is contaminated, substances such as bacteria, chemicals, or other pollutants can alter the characteristics of the water. For instance, water may appear discolored, develop an unusual taste, or emit a strange odor due to the presence of contaminants. These changes typically serve as warning signs that the water quality has been compromised and that further investigation or testing is required to understand the cause and address any health risks.

The other options do not show signs of contamination. For example, consistent water temperature, a steady water level, and clear, odorless water often indicate a stable and normal well environment, rather than an indication of contamination. Each of these factors may represent the desirable qualities of water from a well if no contaminants are present.