Why is it not advisable to use a gate valve on a lawn sprinkler?

Using a gate valve on a lawn sprinkler is not advisable primarily because it may fail to close tightly. Gate valves are designed for fully open or fully closed positions and are not intended for throttling flow. Over time, the seating surfaces can wear down, leading to leaks when the valve is closed. This can result in water wastage or inadequate pressure for the sprinkler system, which significantly diminishes the overall efficiency and effectiveness of watering the lawn.

While the other choices highlight potential issues related to pressure, operational difficulties, or cost, these factors are not as critical as the inability of a gate valve to create a proper seal. The failure to close tightly poses a direct impact on the functionality of the sprinkler system, making it a key reason to avoid using a gate valve in this context.