The title is a pun on the phrase "plumber's crack".
In his comfortable Looneyville house, Elmer Fudd has just filled himself a glass of water from the kitchen sink when he notices the faucet dripping, so he turns it off because the town is facing a drought. He has a serious leak, so he calls plumber Daffy Duck, who claims to be qualified despite wearing a hat with a hammer embroidered on it. Daffy identifies the type of leak as tap water before being questioned by Fudd about his professional qualifications. He then uses his own body to block the leak from the faucet, pipe, soap bottle, cupboard, and Elmer's ears, but he fills up with so much water that it comes out his own bill, prompting Fudd to question his work experience. Daffy turns to Plan B, in which he plays a wrench like a pungi to charm a camera snake into doing his bidding and survey Elmer's pipes.
However, the snake goes up Fudd's trousers and instead permits Daffy to survey his body, which he mistakes for the sink pipe and negatively comments on Elmer's body hair and facial features. He uses a joystick to survey further inside the "pipes" and claims that there is a really small brain inside. A peeved Fudd once again questions Daffy's procedure, before a pipe is immediately thrown at his head. Daffy takes out the pipes and everything in Elmer's house that is fed by them, including a washing machine, a bathtub, an angel water fountain, and a toilet, but not before letting loose his plumber's crack. Still, the leak has not been solved, so a furious Daffy shuts it off at the source. Out back, he ties a large knot in the pipe, causing the dam to reach its breaking point. Arriving back at Elmer's, he is told that the leak still isn't fixed and suggests turning the knobs.
Finally seeing that the sink is no match for Daffy, Fudd angrily strangles the duck to reprimand him on his lousy effort, unaware that the dam has broken, and his house is engulfed in the chaos. Arising from the flood, Elmer tearfully grieves over the remains of his home before Daffy tells him that the leak has been solved and zanily bounces away.