Here's a sewer foreground to go with the background I made last year. This set includes sewage waterfalls, sewage water, walls and ground with sludge, holes with peeking eyes or without, and pipe connectors with or without valve handles.
Skewer's comments: An alternative for those who don't want to use the YI Sewers; these are very nicely done. The flowing water could've been better though. Either way, this is a very nice looking original tileset that I'm sure many will find useful for their cave levels.