Which tool is typically used for tightening plumbing connections?

The tool typically used for tightening plumbing connections is a crescent wrench. This adjustable wrench features a movable jaw that allows it to grasp nuts and bolts of various sizes, making it particularly useful for plumbing tasks where connections frequently involve hexagonal nuts and fittings. The design of the crescent wrench enables a secure grip, which is essential for applying the necessary torque to ensure that connections are tight and leak-free.

In plumbing, proper tightening of connections is crucial to maintain water pressure and prevent leaks. The use of an appropriate tool like a crescent wrench allows for this precise adjustment without damaging the plumbing components.

Other tools listed do not serve this purpose effectively. A flathead screwdriver is primarily designed for driving screws and would not provide the necessary leverage or grip to tighten plumbing connections. A hammer is intended for driving nails or adjusting materials, which is not applicable to connection tightening in plumbing. Lastly, a plumb bob is a tool used for establishing a vertical reference line, not for fastening or tightening. Thus, the crescent wrench is the optimal choice among the options provided for tightening plumbing connections.