Which type of well is temporarily operational during the unavailability of the primary source of water?

A standby well serves as a backup source of water and is utilized when the primary water source is unavailable. Its design and function are specifically intended to provide continuity in water supply, ensuring that operations or processes reliant on water do not face disruption.

In contrast, a test well is primarily used for evaluating potential water supplies and does not serve as a reliable backup; a dewatering well is focused on draining groundwater for construction and excavation processes rather than for consistent water supply; and an observation well is used to monitor water levels and quality, not for water extraction during primary source outages. Each of these other well types has distinct purposes that do not align with the need for a temporary operational water source when the primary is not available, making the standby well the appropriate choice.