What device routes water around the softener in bypass mode?

The bypass valve is the correct answer as it serves the specific function of directing water around the water softener when the system is in bypass mode. In this mode, water flows directly from the inlet to the outlet without passing through the softening process. This can be useful for maintenance, repairs, or if soft water is not needed temporarily.

In contrast, the control valve manages the flow of water through the softener during regular operation, and a flow meter measures the volume of water usage in the system but does not directly route water. A dry contact water meter typically provides signals to alert or manage systems based on water flow but does not handle routing water itself. Thus, the bypass valve is essential for controlling water flow in situations where softening is not required or during maintenance.