After how many hours of continuous pumping must a complete physical and chemical analysis be performed on a new well?

The correct response is that a complete physical and chemical analysis must be performed after 36 hours of continuous pumping from a new well. This time frame is critical because it allows for the stabilization of the well's water quality, enabling a more accurate assessment of the groundwater's characteristics.

During the initial hours of pumping, the water may still contain sediments or contaminants that can distort the results of tests. By waiting for 36 hours, the well has had sufficient time to clear any initial turbidity and for the water quality to reflect the aquifer conditions more accurately. This ensures that the analysis captures important parameters such as pH, dissolved solids, contaminants, and other significant chemical constituents in the groundwater.

Using a shorter time frame, such as 12 or 24 hours, could lead to findings that do not represent the actual quality of the groundwater, since it may still be impacted by drilling fluids or sediment disturbance. Conversely, waiting too long, like 48 hours, may not be practical in terms of operational efficiency and could possibly introduce changes in water parameters due to prolonged stagnation in the well. Therefore, 36 hours is the established standard for conducting a thorough analysis of a new well's water quality.