Water quality must be tested to assess efficacy of the water treatment system and general system cleanliness. This is the only way to proof a safe drinking water installation. Sampling and testing must be carried out for the presence of bacteria, both general (aerobic) bacterial species and Legionella bacteria. Depending on the water treatment method, other test may be required.

  • Legionella bacteria count should not exceed 1000 cfu/ltr
  • Total Bacteria Count (TBC) in excess of 500 cfu/ml may indicate that maintenance practices are not satisfactory
  • Where as 4 to 6 sets of samples at least should be collected from different location of hot and cold water systems
  • Tap points that are tested above maximum allowable legionella concentration need to be resampled
 Frequency Max. concentration  Number of tappoints*
Aerobic Count  Quarterly  500 cfu/ml  4 to 6
Legionella  Quarterly  1000 cfu/ml  4 to 6

*Purpose of the number of tap points to be tested is to proof safe drinking water at the location. It could be necessary to test more tap points then the 4 to 6 tap points.