This study extends the Protective Action Decision Model, developed to address disaster warning responses in the context of natural hazards, to “boil water” advisories. The study examined 110 Boston residents' and 203 Texas students' expectations of getting sick through different exposure paths for contact with contaminated water. In addition, the study assessed respondents' actual implementation (for residents) or behavioral expectations (for students) of three different protective actions – bottled water, boiled water, and personally chlorinated water – as well as their demographic characteristics and previous experience with water contamination. The results indicate that people distinguish among the exposure paths, but the differences are small (one-third to one-half of the response scale). Nonetheless, the perceived risk from the exposure paths helps to explain why people are expected to consume (or actually consumed) bottled water rather than boiled or personally chlorinated water. Overall, these results indicate that local authorities should take care to communicate the relative risks of different exposure paths and should expect that people will respond to a boil water order primarily by consuming bottled water. Thus, they should make special efforts to increase supplies of bottled water in their communities during water contamination emergencies.