How much water should I drink while taking Lasix for edema?

It depends on how bad the edema is. When I was sick with liver issues, I had to monitor my fluid intake daily (by using digital scales to monitor body weight twice daily and logging it in a journal) because if I consumed too much fluid, the Lasix could not eliminate the excess. As a result I could calculate how much I could drink each day to keep the edema more manageable.