"Water is for water,' was only permitted in the beginning of Islam. Then it was prohibited."  

إِنَّمَا كَانَ الْمَاءُ مِنَ الْمَاءِ رُخْصَةً فِي أَوَّلِ الإِسْلاَمِ ثُمَّ نُهِيَ عَنْهَا  

a similar narration (as Hadith no. 110) from, Az-Zuhri, with this chain.  

"Water is for water' is only about the wet dream."  

إِنَّمَا الْمَاءُ مِنَ الْمَاءِ فِي الاِحْتِلاَمِ