Musannaf Ibn Abi Shayba 1:1503

Abu Khalid al-Ahmar narrated to us, from Ibn ‘Ajlan, from his father, from Abu Hurayrah, who said: The Prophet (may Allah bless him and grant him peace) said: "None of you should urinate in stagnant water, nor should he perform ghusl (ritual bathing) in it due to janabah (major ritual impurity)."