A 650 litre tank doesn't hold 650 litres, it's strapped down and all that's in the van is 1 x 25 clx, 100 m micro bore on reel, leisure battery and pump, small telescopic ladder and that's all they have in, my vans are single operator vehicles as well, admittedly they are on the limit at the start of each day but that obviously decreases as water is used