Which statement describes a disadvantage of surface water?

• A. A It is always free from contamination
• B. B It has a fixed year-round flow
• C. C It is easy to contaminate, requires more treatment and security
• D. D It requires less treatment than groundwater

Answer: (C)

Surface water sources like lakes, rivers, and streams sit in the environment where they can easily pick up contaminants from rainfall runoff, agricultural and urban activities, and wildlife. This exposure means water from these sources is more prone to contamination and can vary in quality over time. Because of that, utilities typically need more extensive treatment to remove microbes, organic matter, and chemicals, and they must implement stronger security measures to prevent tampering or contamination. That makes the statement about surface water being easy to contaminate and requiring more treatment and security the best description of its disadvantage. In contrast, surface water is not guaranteed to be contamination-free, its flow isn’t fixed year-round, and it generally needs more, not less, treatment compared with groundwater due to higher variability and microbial load.