A new criterion to determine transmissivity measurement location for groundwater quality management models is proposed. The transmissivity is represented as a random field with known mean and covariance function, conditioned to existing measurements values. The criterion is the minimization of the coefficient of variation of the optimal remediation cost distribution. This distribution is computed numerically by means of Monte Carlo simulations in which each optimal remediation cost is evaluated by solving a deterministic management problem, where the transmissivity is a single realization of the random field. The coefficient of variation is equivalent to the relative error in the prediction of the optimal cost and is shown to be invariant with respect to the actual (unknown) measurement value according to some limiting conditions. In the more general case the coefficient of variation of the optimal cost is less sensitive than the expected optimal cost to the actual measurement value. The proposed criterion becomes a useful tool to determine the best transmissivity measurement location when only few measurements have been performed.¿ 1997 American Geophysical Union