Use the Dish water for toilet flushing
When we are out dry camping the thing that limits us the most is fresh water. Our fresh tank holds 60 gallons and our waste tanks add up to 120 gallons. A way to make the fresh water tank last a bit longer is to not waste it for flushing the toilet. Instead we collect the dish water instead of letting it go down the kitchen drain we use it to flush the toilet. Some folks collect shower water. A pitcher sitting by the toilet does the trick and the soapy water actually helps clean the black tank.