The electric field gradients for dilute alloys of copper with fourth- and fifth-row impurities are calculated. The change in the charge distribution proposed by Alfred and Van Ostenburg, which includes preasymptotic contribution, is used to evaluate the valence-effect contribution. The size-effect contribution is adopted from Sagalyn and Alexander. The calculated values for electric field gradients (EFG's) and asymmetry parameters ($\ensuremath{\eta}'\mathrm{s}$) are found in close agreement with experimental values for almost all the alloys. The results are also compared with other available theoretical results. An attempt is also made to correlate the magnitudes of EFG and $\ensuremath{\eta}$ with the magnitudes of the impurity effective charges which are estimated with consideration of the bound state and size effect.