I was released from hospital 5 days ago with kidney stone. was told 6mm. been drinking lots of water. how much time is needed for stone to pass?

Depends: Spontaneous passage depends on size(diameter)of stone: Under 5mm:75%,5-7mm:60%,More than 7mm:under 40%. I am sure you were told to strain your urine. If no passage in 2 weeks it is probably a good idea to intervene by your urologist. Also if pain control is a problem. Location of stone is also a factor.Follow your urologist's recommendation. Best wishes for you.

Kidney stone: IF you have never had or passed the stone there is no timetable. First of all, there is about a 35 to 30% chance that you will pass a stone that is 6 mm. As long as your pain is tolerable, you can keep trying to pass the stone. IT can days to weeks