Is it safe to drink if you think you may have kidney failure?

Nothing...: If you really think you have true renal failure, where you are producing no urine, then you need to severely limit fluid intake unless you are on dialysis. If on dialysis, your fluid allotments are very, very carefully calculated by your nephrologist and you should follow those instructions to the ounce. Taking too much more could drown you in your own fluids. Have this discussion with kidney doc!

Fluid intake: If you are asking about drinking water, juice, etc. When you think you have renal failure the short answer is "yes with moderation. If you are talking about alcohol, i would not recommend it, but i would strongly suggests you discuss this with your doctor. The first priority here is deciding if you do or do not have renal disease and if so what type, etc.