How do I make a simple water leak sensor?

I'm making a simple sensor that detects if the water is leaking. I want it to have 1 or 2 transistors and 1 relay. it will use 24V power supply. how do I connect everything to make it work? (probes, resistors, transistors, relay, and power supply) Doesn't have to be the exact components but please keep it simple. Any suggestions are welcome. Thanks!