Translation:Shulchan Aruch/Orach Chaim/7
7: The obligation of blessing "Who created man", during the entire day, after using the restroom.
1 Any time that one uses the restroom, whether one urinates or defecates, one should make the blessing: "Who created man", but not "... over the washing of the hands", even if he wants to learn or pray immediately. Gloss: Even if his hands were dirty as a result of wiping himself off, he still does not say "over the washing of the hands." (Sefer Mitzvot Hagadol, Section 27, Positive Commandments).
2
If one urinates but does not wipe himself, then even though one must bless "Who created man," he is not required to to wash his hands except for the purposes of cleanliness or "Prepare thyself".
3
One who uses the restroom and puts aside his attention from using the restroom, and afterwards uses it again must say "Who created man" twice.
4 There is no specific amount of urinating required, because even if one urinates a single drop one must bless, because if one's opening would have been blocked from urinating that drop, it would have been difficult for him, and he is required to thank.