Keep a container (Tupperware type is good) near the faucet to catch the cool water, then use it for hand washing, toilet flushing, etc.
At least one guy installed a two-way valve to re-direct the water back to the fresh tank.
2019 Coachmen Freedom Express 192RBS
2015 T12RBST Flagstaff Hardside
Disclaimer: The actual value of my "Two Cents" of advice varies just like a bitcoin.