One topic that continues to percolate in both the comments to our forum and in the broader conversation about water concerns the possible use of wastewater, treated to extremely high standards, that would be piped back to San Diego’s water reservoirs. There it would be blended with other freshwater supplies before being ultimately drawn down, treated again, and then distributed throughout the city for potable reuse.
Fair disclosure: My late-father, William H. Bruvold, built an academic career at U.C. Berkeley’s School of Public Health studying the public’s perceptions about reclaimed and recycled water and spent time consulting in San Diego. (For an accessible summary of some of his research on this topic see this paper from the journal Water). By looking at a myriad of surveys my father came to some conclusions. They included:
1) Science matters but isn’t determinative. Information and data about safety only moves some subgroups.
2) Information from TRUSTED sources matters a great deal. In other words, people may not feel comfortable about trying to figure out water issues or distinguishing between the effectiveness of various ways of treating water to tertiary standards but do take cues on this issue from sources which they have trusted in the past. If trusted sources say it is safe people will become much more accepting.
3) Acceptance of potable uses usually followed use of reclaimed water for non-potable purposes.
4) (A finding that is my favorite) People’s perceptions about the taste of their water is inversely correlated to their level of acceptance of reclaimed/recycled water. When people say their tap water tastes “bad” people are more reluctant to accept reclaimed and recycled water.