The odd one word is  

Why? 

"crack" refers to solids; "spill" and "flood" both involve liquids.

The odd one word is  

Why? 

"leak" refers to liquids; "come off" and "crack" can both refer to pieces falling off an object.

The odd one word is  

Why? 

"stopped up" usually refers to solids; "flooded" and "leaking" refer to liquids.