A washing machine that works with very low water pressure ...
We have a very small Haier washing machine (it fit in the back of a GeoMetro when we bought it). You can fill it from the hose attachment, or you can fill it with a bucket, so if it doesn''t work on low water pressure there is a way around like it because I can run the wash water into the adjacent laundry sink and use that water to presoak the next load.