I get asked a lot where I came up with my name, Grey Water. I started out in photography underground, photographing sewers. I doubt there are many "drainers" on this site, so here's my best. I haven't gone underground in a long time now, I kinda miss it compared to chasing kids and HS seniors around.
The image was taken in a large overflow tunnel. This was probably a natural creek 100 years ago. Now it's 50 ft below the surface, and a 12' reinforced concrete pipe. This was taken after hiking in it for about a mile. Backlit, using 10 mil candlepower spot, and a 4000 lumen led flashlight. The mixture of the light temps causes the purple hue.