Oof, water messed with the electrical system but it's good that you've confirmed that the starter works. That's the most expensive part! Next I'd check are the ground wires. Water can cause corrosion on those connections, leading to a poor circuit. I'd start with the ground wire from the battery to the frame and then to the engine block. Take them off, clean them up with a wire brush, and reattach them. Also take a look at the starter solenoid and the starter relay. Water can get into those too and cause the clicking or dead circuit you're hearing. Hopefully a little cleaning is all it needs!