I've built two lavatories with one block space in-between them for my Dupes whose stress levels were so high, I'd think that the amount of vomiting they're doing would outright kill them. Anyways, I have all the plumbing done correctly, I presume. I'm using a very large body of contaminated water for the water necessary for the lavatories, and I have an output area for the water as well, yet none of my dupes are using them. It also states that restrooms are out of order (which I have only noticed now), but it says 6 of them are out of order (I presume), but I only have 2 buildings that would be marked restroom. I have got rid of the outhouse approx. 2 cycles.
(Also, on a side note, why is hydrogen being made? Does that come from wastes such as the dupes projectile vomit?)