I've never looked in a septic tank...If you mean more slime than water, yes. It's got a nasty slimey goo on the bottom of the tank floor, and fuzzy brown algae at the top of the water that sort of looks like bubbles from the tank have..fossilized. Bizarre and nasty. I didn't see anything in it thank goodness, but..why wouldn't they clean the water out anyway?! Good grief..