Recommended for high-precision testing for the presence or absence of total coliform and E. coli bacteria in drinking water. These two common potentially harmful bacteria indicators are of particular concern for people served by private wells or springs–as nearby contamination can enter into the ground water supply. Presence/absence testing for coliform and E. coli continues to be industry standard practice, as ANY coliform and/or E. coli detection is considered to be a problem and should be addressed–regardless of the colony count.