It is narrated from Sayyiduna Hudhayfah (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) walked to the rubbish heap of some people and urinated standing. Then he called for water; I brought him water, and he (peace and blessings be upon him) performed ablution and wiped over his leather socks.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 1279