Adams describes his seven tray print washing method (with a photo of a young John Sexton, then his assistant) in The Print, which he used during a water shortage. The basic idea is to set up seven rinse trays, and periodically dump the first tray, refill with fresh water, and move it to the end of the line, promoting the other six trays up the line.
You don't list your location in your profile, but if you have ready access to sea water, you can also use that to rinse film and prints, saving your fresh water for the final rinse. Salt water may even displace fixer better than fresh water, like a hypo clearing agent, but who knows what else is in sea water. It's been used that way on shipboard darkrooms.