MY ADVICE :buy an old car cus pure water is more aggressive than tap water,then buy another one the same make and strip your old one for parts,so if you did breakdown at least you could bolt on the spare part,going to do this with my lwb tranny, but it seems to not want to go into retirement
2 years loaded with 1,300 litres of water sometimes [ still going strong never let me down in two yrs]
]