When you board the plane – keep an eye on the refueling. 18 months ago a local airline accused Pertamina employees of adulterating the fuel and selling the excess. The only problem was they were mixing it down with water. Literally watering down the fuel. This scam was discovered after the airline's maintenance crew, when they opened the tanks, found they had to drain out an excess of condensed water. After complaining the airline was reprimanded for causing trouble and the whole fiasco was swept under the carpet.
That has to be the biggest load of .... I have read in a long time.
You cannot "water down" fuel with water. All avtur aircraft fuel tanks will have small amounts of water within.