Our do-it -yourself EPA based test allows you to screen your water for dangerous levels of bacteria.PurTest Bacteria Test allows you to screen your water for E.coli (Escherichia Coli) and coliform bacteria which if present, indicate the possible existence of harmful bacteria. Nitrates and Nitrites can pose serious health risks, especially to infants. The EPA Maximum Contaminant Level for nitrates is = 10 ppm, nitrites = 1 ppm. If an unsafe condition is present because of Bacteria or Nitrates/Nitrites. Fast, Easy, Accurate. 1 Absence / Presence test for coliform or e-coli bacteria in drinking water. Test kit includes 2 free tests for nitrates and nitrites. All water tests are lab certified. Bacteria Test Instructions:Take out the Bacteria Test vial and set upright on a flat surface.Collect water sample or turn on tap to a very slow stream.Carefully twist off cap and fill vial 1/2 inch below the top (to 5 ml line).Do Not Overfill Or Spill the bacteria growth powder in the vial.Replace cap and twist on tightly. Shake the vial vigorously for 20 seconds.Place the capped vial upright in a warm area (70° - 90°) where it cannot be disturbed for 48 hours. (Do Not Set In Direct Sunlight)After 48 hours, observe the color of the liquid WITHOUT opening the vial.Purple Color: Negative Result ( Original color, no Bacteria were detected).Yellow Color: Positive Result (It is highly likely that potentially harmful bacteria were detected).For positive results, add bleach to the sample before pouring down the toilet, then wash hands thoroughly. Negative sample may be poured directly into the toilet. Discard vial in trash.Note: Please keep out of reach of children and pets. Please note that PurTest is a screening test and can not be used to certify wateras safe or unsafe for drinking.