´It was narrated that 'Aishah said:` "The Prophet went out to urinate, and 'Umar followed him with water. He said: 'What is this, O 'Umar?' He said: 'Water.' He said: 'I have not been commanded to perform ablution every time I urinate. If I did that it would have become a Sunnah.'"
Related hadith on this topic
Explanation & Benefits
Shaykh Umar Farooq Saeedi
Benefits and Issues:
This narration is weak in its chain of transmission; however, remaining in a state of ablution (wudu) at all times is a good deed, but it is not obligatory.
Source: Sunan Abu Dawood – Commentary by Shaykh Umar Farooq Saeedi, Page: 42