This research report presents results of a study designed to investigate the effects of including a provision rule in choice modelling non-market valuation studies. Split samples with and without a provision rule were used to test for differences in household willingness to pay (WTP) for improvements in environmental quality in the Hawkesbury-Nepean catchment. Local/rural and distant/urban sub-samples of residents were selected. The results of the study show that the inclusion of a provision rule had an effect on preferences in the distant/urban communities. However, the impact of a provision rule in the local/rural community sub-samples was negligible.