I just commented on another dream, which reminded me of this dream, which I had last night. I felt inspired to post (sorry if it is a personal, not prophetic dream).
I dream that I went down a sewer with three other people, I think for protection. It was dark, but there was no water or odor at all. I was surprised at how spacious it was. Two people found treasure down there that we could use in the future. I got distracted by a voice that I assumed was the Holy Spirit. The voice had me go off to the right, through a tunnel leading outside. I saw some zombies wandering around. I stepped too close and they pulled out handguns and started shooting at me. The noise attracted a large horde. About a quarter of them had guns, too. They killed me and I kept respawning and dying, like in a video game. I found myself wishing that I stayed in the sewer.
I have had many dreams about toilets both dirty and clean. I feel they always covey a message about sin. I have felt dirty after waking. Maybe the dirty sewer literally means sin and the sin will be cleaned/removed. We can only clean the sin through jesus and repentance. We all need to repent.