OK, this is not going to be a popular post with many. When you are talking long term and "lights out" there hasn't been any improvement in over two centuries on how to do clothes. Unless you live alone and only have two sets of clothes, things like "Wonder Wash" etc. manual agitation machines are a gimmick. They are quickly overwhelmed by any volume at all. Think for a minute the volume of clothes you wash now and even cut it in half then think of doing it in a five gallon bucket?
Its popular in this modern society to think before widespread use of electricity that people went dirty and wore the same clothes all the time but that wasn't the way it was especially in the 20th century. People lived in the country and worked in the cities just like today despite a major disparity on services. Wash day was on a home calender because daily washing was and still is impractical when you are doing it manually for a family. Manually heating and transporting water daily to do mini-washes simply is a terrible waste of time and labor.
We spend a fortune on gimmicks and gizmos but I bet few people know a good galvanized wash tub and wash board cost less than $100 and even fewer have them. The part left out of our good friends book "Lights Out" was all the people with bruised ribs and knees and sore from bending over trying to wash clothes in modern bathtub. There's will do in a pinch and then there's long term. Most of the plastic gimmicks and gizmo's will be busted in a matter of weeks.
Many will be thinking with all our other survival stuff, we don't have room for a couple nice galvanized wash tubs. Yet I bet everyone of us has plastic storage bins. Unless you are using them for washing, they take little space as you can fill them with whatever. I even use one of mine for catching rain water. Most of my family has the oval ones they use to store wood but in needed, there they are. In fact, all a laundry basket is, is a lighter version of just one application of the old wash tub which doubled as a way to haul your wet clothes to the clothes line.
Some people who have it figured how to continue having running water have it really made by having a wash sink, which is just another offshoot of the old wash tub.
I know this sounds like stepping back in history but if you have power, life is chess game not checkers. Things like heating and hauling water become bigger deals. There was a reason before widespread electricity laundries and wash women type jobs were very popular. In fact in some "Mad Max" type EOTWAWKI or heck even if the liberals have their way and power becomes such a premium these windmills and solar stations without a 50% government subsidiarity become widespread, they may become again one day.
Tj