What about taking a shower in between dreadlock washing days? - Dreadlocks FAQ's
A lot of people, due to their lifestyle, need to take showers ever day. (although some of them are apparently not aware of it =) So what do you do if it's not time to wash your dreads and you need a shower? Can you get them wet?
Getting the dreads wet ahead of time won't usually cause them any problems, but many people find that if they get their dreads wet without washing them and getting them clean, they get itchy sooner. If you don't find this to be the case then you can get them wet in between washings. Of course you need to make sure they dry fully. You don't want to ever let them sit wet for long periods.
If you don't actually need to rinse them it's probably easier to just keep them dry. I've found the easiest way to keep my dreads dry in the shower is to wrap them in a towel or use a shower cap. That way any overspray from the shower is absorbed by the towel. A shower cap would work too (if it was large enough and didn't look completely retarded) but who has a shower cap handy? I always have a towel and it only takes a second to wrap'em up.
So what if you play a sport and sweat like an ape? Unless you don't mind perpetuating the "dreads are smelly" rumor you'll pretty much have to at least rinse your dreads when you get them really sweaty. If they are new and delicate just be gentle with them, they will be fine. This is one of the reasons rubberbands are used on the roots and tips, they make young dreads more durable and prevent them from loosing knots. Also, if it's only one day before your scheduled wash it should be fine to wash them a day early. You're always going to have some loose hair after washing new dreads but it's easy enough to take care of, and once you do, it will be less loose hair to pop during your next shower.