Sayyiduna Amir bin Rabi'ah (may Allah be pleased with him) said: The Prophet (peace and blessings be upon him) stood at the grave of Sayyiduna Uthman bin Maz'un (may Allah be pleased with him), and by his (peace and blessings be upon him) command water was sprinkled on his grave.
Al-Bazzar recorded it, and its narrators have been declared trustworthy; however, the case of al-Bazzar's teacher Muhammad bin Abdullah is different, as I do not know him.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الجنائز / 4249
Hadith Gradingمحدثین:إسناده ضعیف
Hadith Takhrij«اخرجه الامام البزار فى المسند (843) ، أخرجه مسند البزار برقم: 3822»
Sayyidah Aishah Siddiqah (may Allah be pleased with her) said: The Prophet (peace and blessings be upon him) sprinkled water on the grave of his son Sayyiduna Ibrahim (may Allah be pleased with him).
Al-Tabarani recorded it in al-Mu'jam al-Awsat; apart from al-Tabarani's teacher, all the narrators of this report are the narrators of the Sahih.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الجنائز / 4250
Hadith Gradingمحدثین:إسنادہ حسن
Hadith Takhrij«أخرجه المعجم الأوسط للطبراني برقم: 6142، وأخرجه مسند الإمام الشافعي برقم: 602، وأخرجه معرفة السنن والآثار برقم: 7722، وأخرجه شرح السنة برقم: 1515، وأخرجه السنن الصغير للبيهقي برقم: 1119»