What is the purpose of a well screen?

The purpose of a well screen is to filter out sand and sediment while allowing water to flow into the well, which is why this answer is correct. A well screen is typically a perforated or slotted pipe that is installed at the well's intake point. Its design allows groundwater to enter the well while preventing larger particles, like sand and gravel, from entering. This is crucial for maintaining water quality and protecting the pump and other well components from damage caused by abrasive materials.

The well screen ensures that the water collected is as clean as possible, enhancing the efficiency and longevity of the well system. The other choices represent functions that are not associated with a well screen's primary purpose. For instance, storing chemicals or cooling water are not relevant to the physical function of a well screen, indicating that the primary role is solely focused on filtering water infiltration effectively.