Huh, digging around in the textures/effects folder, I found a chunk of texture files that are 0B, which I'm pretty sure shouldn't be the case. Among them are fx_ichorbarrel, fxwaterfallwhitestriplite, fxwatertile01, fxwaterwall, fxwerewolfbody, fxwoodburning, and a handful of others.
Also I'm not using ENB.
EDIT: It seems that all the 0B files are from the STD folder from the STEP guide. Seems like somehow or other it got messed up during optimization.
EDIT2: Yup, that did it. Just took the same files from the extracted STD folder and replaced them. Water is looking fine again. Sure they're not optimized, but I can deal with a few unoptimized texture files. Thanks for helping me work through this.