I have to test for Legionella BUT what is this HCC or HPC or TPC?

So you test for HCC / HPC / TPC but your not sure what it means. Well here is what they stand for –   HCC – heterotrophic colony count, TBC – total bacterial count or HPC – heterotrophic plate count. And what is the difference between them I hear you ask?  Basically nothing, just a different terminology giving you the same outcome.

What do those results indicate to you?

FOR A FACILITIES WATER DISTRIBUTION SYSTEM  –  They are useful to indicate problem areas of microbial regrowth occurring within the facility water distribution system.  It can indicate low turnover of water within your facilities water distribution system, possibly a resident is not showering or restricted to sponge bathing.  However, the result is not an indicator of health risk and the results should be interpreted accordingly by looking at results in total of the whole facility to determine the norm for that result.

FOR A COOLING TOWER* –  the following values you should take the following actions.
<100,000 – System under control, maintain monitoring and treatment program.
≥100,000 to <5,000,000 - Conduct immediate online disinfection, Review your control strategy, Re-test water within three – to seven days of plant operations and assess if further remedial action is necessary.
≥5,000,000 – Conduct immediate online disinfection, Review your control strategy, Re-test water within three – to seven days of plant operations and assess if further remedial action is necessary.
*Please refer to AS3666.3 table 3.2 for further information.

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