As a somewhat experienced boondocker I can offer a few suggestions. First, you have to manage your gray water before it goes into the tank. We catch the shower water while waiting it to get hot to water the dogs. The excess goes to water the landscape since it is not technically gray water. We catch kitchen sink water while waiting for it to get hot to make coffee or fill canteens for hiking or ATVing. We catch the kitchen sink water while waiting on it to get hot. Lots of happy plants. You are not dumping gray water if you follow these suggestions. You can stretch your gray water tank for several day using this method.