Sheikh Ahmad Kutty, a senior lecturer and an Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, states: “Urinating while standing has been considered by some scholars as makruh or undesirable simply because of the fact that doing so may cause urine to splash on our body or clothes. We should therefore avoid it unless we are faced with a situation where we have no other choice: for instance, while using a public washroom, if there is a concern of exposing ourselves to communicable diseases if we were to do so while sitting on the toilet.
Makruh is something considered as undesirable; technically speaking, it refers to actions that we should avoid, and if we avoid it we will be rewarded for it, while, at the same, there is no punishment if we happened to do it. Haram, on the other hand, is that which is prohibited which we must avoid, for if we did it, we would incur sin and punishment. If we happen to pass urine while standing because of certain unavoidable circumstances, we must make sure that urine does not splash on our body or clothes. If it does, we must wash ourselves clean before we are eligible to perform prayer.”
Sheikh M. S. Al-Munajjid, a prominent Saudi Muslim lecturer and author, adds: “The Sunnah is to answer the call of nature sitting, making oneself close to the ground, because this is more concealing, and makes it less likely that spray from one’s urine will come back on one’s body or clothes, making them dirty. If a person can be sure of avoiding this, then it is permissible to urinate standing up.”