Closer examination of basic water treatment processes, "source to tap", is one of the evident supplier responses to new quality constraints and increasing resource pressures. More recent, with the release of incident reports and Cryptosporidium documentation, the focus has been extended to defining and operating at "optimal" conditions within treatment processes. As a result, the water industry is currently re-evaluating the "due diligence" guidance of operational procedural practices on treatment streams, in order to consistently produce potable water to an ever increasing standard, thus lowering the public health risk.