I confess, I'm not actually all that interested in the sanitation part of the plans. In part because the canon shows the Elemental Nations going from quasi-medieval technology
to relatively modern within a few decades (so they'll get there eventually, with or without our help) but also because it strikes me as playing too close to realism for me to really get into it. When reading Eragon, Harry Potter, Mistborn, etc., most readers/authors don't mention the nitty-gritty details of how sanitation works unless it's relevant to the plot or influences the central themes of the story (fucking J.K. Rowling). In Eragon, for example, most everyone would be shitting in buckets and dying of disease before they reached thirty. But that's not exactly conducive towards immersive storytelling (realism vs immersion debate) so most authors don't bother.
But my general apathy towards this new sanitation direction isn't all that strong. I'm willing to be proven wrong and I'm cautiously interested to see how it's implemented, story-wise. Sorry if this is me being a downer! I'm not trying to rain on your parade! I'd just sorta assumed --in the back of my mind --that there was some basic level of sanitation (baths/toilets) for ninja, since refrigerators existed in canon around this time and because MfD's Orochimaru had ready access to pipes and running water. I'd just kinda assumed it was a "perks of being a ninja or a particularly wealthy merchant" thing. Or, perhaps a "perks of jonin ninja" thing, where the costs were so prohibitively expensive that only the wealthy elite could afford it. So this sudden interest is, for me, coming out of nowhere and it has me a little bemused. I hope that explains my opinion.
Again, not trying to diminish anyone's enjoyment over a good civilization-warping, societal changing, technological advancement! I'll still delve into discussions on the topic and vote for plans that contain engineering stuff. It's just not my main interest, so my contributions towards this particular thing may be a bit... lackluster, as far as general hivemind discussions go.