Thank KB & others.
Regarding the size of the water tank, I can't remember what the exact size, but I know it's 100 and something.
It is a CENTRAL COAST CAMPER TRAILER. The owner/builder Terry mention that he used to put 60 litre tanks in, but supplier has come up with much larger tank at very small increase in cost, so he has upgraded tanks size at no extra cost
'shakey'