End stage kidney disease, or renal failure, occurs when your kidneys are no longer able to support you in a reasonably healthy state, and dialysis or transplantation is needed. This happens when your kidneys function at only 10 to 15 percent.
Dialysis treatment is needed when your own kidneys can no longer take care of your body's needs. You need dialysis when you develop end stage kidney failure, usually by the time you lose about 85 to 90 percent of your kidney function and have a GFR of <15.
For more information about dialysis see Dialysis - National Kidney Foundation.