*2.2. Distribution*

We used a four-stage drop-off pick-up method adapted from Trentelman et al. (2016) to distribute the questionnaire [51]. Compared to other distribution methods, drop-off pick-up methods have an increased emphasis on social exchange and personal rapport created from in-person interactions, allowing one to garner a higher response rate than mail or phone survey methods [50–52]. We expected that the lack of water quality issues in the Roanoke area would result in low salience of the topic among residents and reduce interest in survey participation. We adopted the drop-off pick-up method to offset this effect and heighten the survey response. Both the questionnaire and distribution methods were approved for use by Virginia Tech's Institutional Review Board.

We sent introduction letters to each resident between September and November 2019, informing them of our study and intended visit. One week after the letters were sent, our research team visited residents' homes to provide them with information about the study and invite them to participate. We mailed introductions to groups of about 100 houses per week to allow us time to visit all residents' homes no more than two weeks after they received the letter. To maximize the likelihood that residents would be home from work, we scheduled visits between 4 p.m. and 8 p.m. on weekdays and between 10 a.m. and 4 p.m. on weekends. To ensure uniform interactions, team members adhered to a script adapted from the guidelines that Dillman et al. (2014) and Trentelman et al. (2016) presented [50,51].

If they agreed to participate, residents were given a survey to complete at their convenience and a doorknob bag to deposit their survey and leave outside for us to pick up two days later. We made up to two follow-up visits, as needed to contact residents and pick up completed surveys, waiting two days between visits to allow ample time for them to complete the survey. If a resident was not home when researchers arrived at their door and a survey was not left outside for pick up, researchers would leave a note on the door saying, "Sorry we missed you, we will be back on [insert date]," and attempt that visit again two days later. The note established the research team's reliability because the participants had been told what date to expect the team's return. We made up to three attempts per visit to contact a resident. After a third failed visit, we left a packet by the resident's door with a note explaining our contact attempts, a cover letter, the survey, and a postage-paid envelope for the survey's return. If the third failed attempt was on an introductory visit, we also included a letter introducing the study and requesting participation.

We first visited homes closest to our base location west of Roanoke and progressed east. We started data collection in September 2019 but halted operations in November when daylight saving time restricted sunlit working hours. The COVID-19 pandemic prevented us from collecting data again in spring 2020. This reduced our sample from 792 to 611. The remaining 181 addresses were located to the northeast of Roanoke. Potential differences between neighborhoods sampled and unsampled may reduce the generalizability of our results to all residents in the greater Roanoke area. To examine the potential for this, we conducted a test of proportions to compare the respondents in our reduced sample with the 2017 data on race from the U.S. Bureau of Census. Race is a demographic variable commonly associated with water quality issues [19,53], and our results indicated no differences see [27].
