Common themes contributing to recent drinking water disease outbreaks in affluent nations

New Zealand experienced its largest waterborne disease outbreak in modern history in August 2016 with 5,500 cases and four fatalities. This recent outbreak is one of 24 drinking-waterborne disease outbreaks in affluent nations that have been reported in the scientific literature since the infamous Walkerton, Ontario, Canada fatal outbreak (2,300 cases, seven fatalities) in May 2000. These disasters were all eminently preventable given the economic and intellectual resources existing in the countries where they occurred. These outbreaks are analysed according to major recurring themes, including: complacency, naiveté and ignorance, failure to learn from experience and chemophobia. Lessons that can be learned to improve preventive approaches for ensuring safe drinking water are based on an extensive and authentic body of evidence in support of meaningful improvements. Philosopher George Santayana captured this need with his famous quote: ‘Those who cannot remember the past are condemned to repeat it.’