Advancements in nano- and biotechnology are leading to highly absorbent and specialized materials. Just recently a paper by Seth Darling et al. (link below) introduced a new, reusable sponge that can absorb oil 90 times its own weight. By using such materials to absorb stains, dirt, bacteria, the washing machine requires much less water, energy and time.
This would be beneficial, particularly for customers with older machines. Different sets of sponges can thus make the washing process more efficient and effective, cleaning the clothes in a much better way, and with more convenience.
Unfortunately, I am not a chemist or nanotech expert. It is merely an idea that introduces something different then detergent + water mix or existing measures to reduce water usage.
paper: http://pubs.rsc.org/en/content/articlelanding/2017/ta/c6ta09014a#!divAbstract article: https://news.uchicago.edu/article/2017/03/07/argonne-invents-reusable-sponge-soaks-oil-could-revolutionize-spill-cleanup
pic credit: 1: http://quornblog.weebly.com/uploads/2/0/6/3/20638130/7406767_orig.png 2: https://cdn3.volusion.com/kcqfe.xztck/v/vspfiles/photos/Sponges-3.jpg?1480696451