I am finishing my Tiny House here in Montana. It's one of those portable ones a la Tumbleweed houses. And what's the biggest challenge? Electricity? NO! That's easy, with Solar panels, a few big batteries, and some used 12v car and RV appliances. Is it POOP management? No--composting is pretty straightforward. The BIG challenge is water. I designed the house to be able to freeze without damaging anything. And it's portable, which is fun. The big question though, is what do we do with the water we use? I designed the drainpipe runs to go straight with no traps, also to avoid damage during freezing. From PVC inside, I switch to fire hose outside. But what to do with the water during freezing temps? Anybody got good insight on freeze-compatible greywater systems?