Weak
graded by Al-Albani
Mishkat al-Masabih 489
Narrator:Umar ibn al-Khattāb
وَعَنْ عُمَرَ بْنِ الْخَطَّابِ رَضِيَ اللَّهُ عَنْهُ قَالَ: لَا تَغْتَسِلُوا بِالْمَاءِ الْمُشَمَّسِ فَإِنَّهُ يُورِثُ البرص. رَوَاهُ الدَّارَقُطْنِيّ
‘Umar b. al-Khattab said, “Do not wash in water which has been exposed to the sun, for it produces leprosy.” Daraqutni transmitted it.
Cited in Mishkat al-Masabih (No. 489).