Evaluation of off-site mitigation entails comparison of utility changes between two sites. Choice modelling has been used to identify community willingness to trade-off attributes for two different types of stream in New Zealand. Estimated utility functions are used to derive marginal rates of substitution and stream attribute part worths which can be used to design or evaluate both on-site and off-site mitigation policy. Latent class multinomial logit models identified classes of citizens who valued stream attributes quite differently. Significant differences in values for some attributes on different stream types imply heterogeneous mitigation ratios across environmental attributes.