if the price of the waters a big factor and it just storage of water tanks and office bits then do what we did in essex ,   and buy a shop with a flat above without a meter ........
the rental income coves more then the morage      , you can then rent the shop to yourself  , no water charges , no rates if the shops a smaller one  , and no tax to pay when buying it as its mixed use win win win ours as parking for three van out the back as well ,
 we will turn the shop into a flat when the boys done with it now hes running that bit of the firm   adding more £££££  worth looking in too you will be surprised how cheap mix uses are these days