How can i reduce leg edema from the knees down on both legs?

Elevation: Keeping your legs elevated generally reduces swelling; diuretics can be used also but something that should be prescribed after a full evaluation.

Many possibilities: Some causes of swelling of the legs can include systemic problems such as hypertension, and problems with the kidneys and localized issues such as arthritis, infection, lymphatic obstruction, blood clots, varicose veins, trauma (fracture, sprain, tendonitis) and side effects to medication. Have it evaluated by a professional and get the appropriate treatment.