Can leek water reduce edema?
Generally speaking, leek water may help alleviate mild physiological edema to some extent, but it cannot eliminate pathological edema. The detailed explanation is as follows:

Mild edema caused by prolonged sitting or excessive salt intake may be slightly relieved by the water and small amounts of dietary fiber contained in leek water, which could promote urination and help remove excess fluid from the body. It may serve as a minor complementary approach for daily management.
Pathological edema caused by kidney disease, heart problems, or other organ-related conditions stems from abnormal organ function. Leek water cannot address the underlying cause, and relying on it blindly might delay appropriate treatment. For such cases, treating the primary disease is essential to resolve the edema effectively.
If swelling persists or is accompanied by other discomforts, it is important to seek medical evaluation promptly to identify the cause and take appropriate action, avoiding self-treatment that could delay timely intervention.