The travel cost method is a commonly used method of valuing recreational sites. Although mail surveys are often conducted to collect data on the costs of travel to the amenity, they usually result in a lower response rate than that of face-to-face interview surveys. As a result, several biases such as non-response bias and sample selection bias will occur. The benefit derived from the consumption of environmental services can be over-/under estimated. We examined whether the rate of non-response varies as the distance from the study site increases, based on the data collected from recent visitors of Ohigawa River, Shizuoka-city. We can conclude that, contrary to our expectation, there is no statistically significant correlation between the non-response rate and distance within 150km of the site.