why waste water washing clothes
Psychological/mental well-being.

After hurricane Jeanne in '04, my neighborhood was without power for over two weeks and this was only three weeks after hurricane Frances had hit just two miles north of there. The amount of clean-up necessary was substantial as the 4th largest hurricane to hit FL happened in an area not hit by anything in over 100 years (a lot of trees that had never seen serious wind before, now all down). Getting downed tree limbs out of canals, roofing/housing materials and other debris moved out of roads/driveways was hot/humid/filthy work. One thing that really lifted people's spirits was being able to bath and then putting on fresh socks/shirts/shorts tomorrow morning when you wake up. By the end, most of us tossed all of the clothes from the prior month in the trash - mangrove mud never comes out. However, washing some clothes every few days to keep a few sets of clean things to wear was one way of keeping the motivation level high enough to go fire up the chainsaw and keep doing that kind of thing, one 95* day after another....after another.

Clean clothes aren't 'necessary', but they do make a tangible difference in a person's mindset during an event.