Originally Posted by bry899
I wouldn't be concerned on the weight of the Gray & Black tanks, unless you keep filling the fresh and never empty the gray or black.
In other words as the fresh gets used up it gets lighter, the gray and black tanks then get heavier.
I don't know of anyone that travels with full fresh, gray and black tanks.
There are also plenty of dump stations available including some rest areas and gas stations, also most campgrounds charge a small fee to just dump ($5-$10).
So usually black & gray weight are not issues
I agree. I have a line for total weight just so I know if for example we drive to my folks' place and can top off fresh water from the house but have nowhere to dump gray/black in their community.
For the rest of the calculations, I figured 10% for each (black & gray).
Total average weight with 6 people, 2 dogs and full tanks =GrossVehicleWeightLBS+(6*154)+(2*60)+FuelLBS+Liqu idPropaneLBS+FreshWaterLBS+(GrayWaterLBS*10%)+(Bla ckWaterLBS*10%)