Cu2+ ion has 17 electrons in its outermost orbital. 4H2O molecules donate 4 pairs of electrons for coordinate covalent sharing. The one H2O molecule is attached to the sulphate ion by hydrogen bonding, the oxygen being oriented to the hydrated cupirc ion. 
Thus, the number of hydrogen bonded water molecule associated with CuSO4⋅5H2O is 1 .