The Prophet Muhammad's ﷺ Eco Wudhu

Regarding water conservation, Abdullah ibn Ámru bin Al-Ás رضي الله عنه (may Allah be pleased with him) narrated that:

'The Messenger of Allah ﷺ (Allah's peace and blessings be upon him) happened to pass by Sa’d رضي الله عنه as he was performing wudhu (ablution).

At this, the Prophet ﷺ said, "Sa’d what is this squandering?"
Sa’d replied: "Can there be an idea of squandering (israf) in ablution?"
The Prophet ﷺ said: "Yes, even if you are by the side of a flowing river.”

(Ibn Majah)