Int. J. Environ. Res. Public Health 2011, 8 573 Place of residence was found to have important effect on the use of bottled water. For example, community size had a positive relationship with being a primary bottled water user. As the community size increased by one ascending category, the odds of the resident of larger community using bottled water for primary drinking purposes were increased by 0.116 times. The use of bottled water as primary source of drinking water was also closely related to where the respondents lived in the U.S. For example, a respondent in the Midwest (region 7), when compared with a respondent living in the southern Pacific region (region 9), was over 80% less likely to be a primary user of bottled water. Similarly, for a respondent in the mountain region (region 8), the odds of the person using bottled water as primary drinking water source were reduced by 53% compared with a resident in the southern Pacific region (region 9). Similar to the southern Pacific region (region 9), the southern region (region 6) and the southeast region (region 4) also have more residents primarily depending on bottled water for drinking (see appendix for detailed regional bottled water use comparison). With logistic regression models, there is no equivalent r-squared statistics to show the explained variability in the dependent variable. However, the pseudo R2 shows that the explanatory variables have moderate strength of associations with consumption of bottled water. The model non-significant chi-square test and likelihood ratio test statistics (1.0), which suggests good model fit [23]. Overall, this model shows that U.S. consumer perceptions about groundwater quality have strong associations on the purchase of bottled water for drinking. This suggests that bottled water use may be considered a substitute for other water sources when groundwater quality is perceived to be poor. 3.3. Logistic Regression Model 2: Regular Bottled Water Users A second logistic regression model was used to predict regular users of bottled water (Table 3). Table 3. Logistic Regression for regular bottled water users (N = 2,850). Variables OR CI 95% Surface water quality 1.049 0.874–1.259 Ground water quality 0.661 *** 0.566–0.771 Environmental attitudes 0.973 0.925–1.024 Age 0.984 *** 0.979–0.989 Community size 1.046 0.981–1.116 Education 1.039 0.965–1.120 Gender (control: male) 1.243 ** 1.035–1.493 Drinking water (control: safe) 1.742 *** 1.307–2.323 Region (control: region 9) Region 4 0.988 0.785–1.243 Region 6 1.144 0.896–1.461 Region 7 0.541 *** 0.413–0.708 Region 8 0.528 *** 0.413–0.676 Small water supply systems Private water supply 1.746 ** 0.560–0.993 Municipal water supply 0.896 0.709–1.132 Pseudo R2 (Nagelkerke) 0.094 Note: * P < 0.10; ** P < 0.05; *** P < 0.001.