Which of the following would likely be most helpful in determining the degree of organic load in a building's domestic water system following a water main break?

The determination of the degree of organic load in a building's domestic water system following a water main break is best assessed by examining chlorine levels in the cold water at the building entry and from faucets. Chlorine is commonly used as a disinfectant in water systems, and its concentration level is a direct indicator of the effectiveness of disinfection and the presence of organic material.

When a water main break occurs, it can introduce contaminants, including organic materials, into the water supply. If there is a significant organic load, chlorine will react with these materials, causing a drop in chlorine levels. Analyzing chlorine levels at both the building entry point and from various faucets allows for a comprehensive assessment of how much organic material has entered the system. This data is crucial because it helps identify the extent of contamination and whether further treatment or corrective measures are needed.

In contrast, while chlorine levels in hot water may provide some insight, the focus commonly falls on the cold water supply because it directly reflects the quality of incoming water before it has been heated (where additional factors may influence chlorine concentration). Water pH levels can provide useful information about water chemistry but do not directly correlate to the presence of organic load. Testing for specific bacteria strains can also indicate contamination, but it does