My lovely 1990 AutoTrail Apache..... I cleaned out the water tanks today, as I am new to the van and decided to measure them. I think that waste tank was just over half full looking at the meter, it drained about 60 something ltrs. So my guess is that is a 100ltr waste tank. I drained and filled the fresh water tank too - it is a 50 ltr tank. So why the mismatch? I would have expected a larger fresh water tank.