GWWI Water Distribution Practice Test 2026 – Complete Exam Prep

Sodium hypochlorite is widely recognized as a primary disinfectant used in water treatment processes. It serves as a chlorine source that effectively eliminates bacteria, viruses, and other pathogens present in drinking water. When added to water, sodium hypochlorite undergoes a reaction to produce hypochlorous acid, which is the active disinfecting agent that disrupts cellular processes in microorganisms, rendering them inactive or dead.

Its advantages in water treatment include being easy to handle, store, and apply. Additionally, sodium hypochlorite provides residual disinfection, meaning it continues to protect against microbial growth even after the initial treatment, which is essential in ensuring the safety of drinking water as it travels through the distribution system.

In contrast, while the other choices serve important roles in various aspects of water treatment, they do not primarily act as disinfectants. Sodium bicarbonate is often used for pH adjustment, calcium chloride is primarily utilized for hardness adjustment and water softening, and potassium permanganate is mostly used for oxidation and controlling taste and odor in water rather than as a general disinfectant.