Plumbing a poem means checking its vertical integrity: whether each descent into detail, memory, or image relates to the central line of attention. A poem can wander widely and still be plumb if its associations deepen one governing pressure. The test is useful for long lyrics, where attractive side passages may pull the work off center. A poet can restore plumbness by repeating a question, returning to a physical setting, or cutting material that does not increase depth.

To plumb a poem is to test its vertical integrity: whether its central movement, emotional descent, or governing idea remains sound from beginning to end. Read the draft as a sequence of load-bearing moments and ask where the poem leans, loses depth, or introduces material that cannot be supported. Plumb is especially useful for diagnosing weak transitions and decorative passages. Related terms include structure, grounding, trajectory, and coherence.