The NMR shielding constants in (H2O)(2) have been calculated using GIAO-SCF, MP2, MP4 and CCSD methods and for a range of basis sets. According to the obtained results the 6-311++G** or aug-cc-pVDZ basis sets are recommended for SCF calculations, and the aug-cc-pVXZ series is suggested for correlated calculations of the interaction-induced changes in the shielding constants. The counterpoise correction improves the results towards the basis set limit and is essential in the case of O-17 shielding. Correlation effects are substantial for the changes in O-17 shielding, less so for H-1 shielding. They are overestimated by the MP2 method.