The EZ-ATP monitors total bacterial and pathogen load in water by measuring portions of ATP (adenosine triphosphate) of any type of bacterial microorganism present in the water sample. These may include fecal coliforms such as E. coli, sulphate reducing bacteria, nitrifying bacteria or Legionella. The analyzer can be used as an Early Warning System in various applications with focus on water safety, when high ATP values indicate a potential risk in surpassing a threshold value of microorganisms in the past or in the near future.