Yesterday, I bought two power cords to use with the test system for the home environmental sensor array. The white power cord will be the sensor itself. One of the wires will send electricity from the pi and the other wire will receive the signal into the pi. The plug end will go in the crock. When water touches the leads, it will complete the circuit and send a signal to the raspberry pi.
The other cable is only for the test system. I will wire it to one of the water pumps I bought. That water pump will represent the sump pump. I can turn the switch off to simulate something going wrong with the sump pump.
I should be able to build the test system the next time I am at the Makerspace.