I really think the goop water is best left stylized. Rather than trying to be realistic in this simple, tiled PA game mockup, a symbolic approach seems to do well.
if you don't agree FIGHT ME
lol, fair point! It is too regular and too agitated for sewer waters now that you mention it. Thanks for the feedback 
Maybe vary the slime tile more? It's all the same bubble form, and I personally like tile variation. Plus I'm not sure how a liquid got that... wavy? Love the brick texture tho (:
I trust your judgment more than mine haha. I still think some tile variation would help though.