&quot;This is the end result of an education system that has not prepared people for the modern world, if we engineer a solution that produces water of a purity greater than water from a reservoir and and half of people are still not sure it is safe to drink then we have a massive problem.&quot;<p>It has nothing to do with the education system and everything to do with human social evolution and evolutionarily stable strategies.<p>You&#x27;re looking at the problem &quot;like a nerd&quot;[1] wherein you have a fixed set of definitions and guidelines and the end product (the water) fits or exceeds all of them and therefore, presto!  Anyone who disagrees with your framework is therefore an idiot.<p>But these people aren&#x27;t disagreeing with the stats - they don&#x27;t care about the stats.  They have a built-in, knee-jerk revulsion to drinking anything that came from sewage.  That <i>might not</i> be rational or useful in 2016, but it has been <i>tremendously useful</i> over the past hundred thousand years of human social evolution.  In fact, so useful, that people without that revulsion have been heavily selected against.<p>If your response to this is to show them more and more data and &quot;proof&quot; you&#x27;re missing the point.<p>[1] ... to use Nassim Taleb&#x27;s technical term.