One switch is on top of cover on back of water heater tank.........that one is to turn electric heat element ON/OFF
The switch and outlet by kitchen sink.........what do you mean by outlet?
Outlet like a regular 120V AC plug?
Outlet like a 12V DC plug?
Switch could be for water heater 'propane' ON/OFF
More info would help.
Sounds like you have an Atwood water heater.....switch on back of water heater and it must be 2003 or earlier model.
The propane..does it use pilot flame or does it have ignitor.
Model #?
One thing for sure....make sure water is in water heater prior to turning switches ON.
Electric element will burn out within minutes. Propane will heat empty tank.