Privacy Settings PWTAG advises members not to use postal testing - Aquacert
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Many pool operators have recently a communication from the Pool Water Treatment Advisory Group which states that the PWTAG advises members not use postal testing for the monthly testing of their pool / spa water.   What the PWTAG mean by a postal service is when the samples are sent to the laboratory using Royal Mail (or similar) and take up to 3 days to arrive at the laboratory.

The Pool Water Treatment Advisory Group have two Technical Notes relating to Microbiological Testing:
  • Microbiological Testing (TN27)
  • Microbiological Testing (TN53)


AquaCert is NOT a ‘postal’ service.

These documents explain:

  1. How to take the water samples
  2. What type of laboratory you should to choose to undertake the testing
  3. How the samples should GET to the laboratory

Why is this Important

The sterile sample bottles contain sodium thiosulphate which deactivates the chlorine in the water, if the chlorine is not neutralised it will continue to kill any bacteria in the water sample whilst in transit to the laboratory. This would obviously give false results.

However, by removing the chlorine – there is nothing to stop the bacteria proliferating so the sample needs to be tested as soon as possible.

Laboratories are overseen by a body called UKAS which set the rules/methods which the laboratories have to adhere to.

For pool / spa samples, these rules include how the sample get to the laboratory.

UKAS decrees the maximum period of time between taking the sample and its arrival at the laboratory, these are

  • Within 4 hours (without temperature control)
  • Within 24 hours (if temperature is maintained between 2-8°C)

It’s obvious that sending a sample by post would not meet these criteria.

You can trust AquaCert

  • AquaCert only use same day couriers that have refrigeration facilities.
  • We monitor our transit performance, during 2021 we averaged just over 6 hours from our clients to the laboratory and that’s with a temperature controlled environment throughout the journey.
  • We easily exceed all the requirements of the PWTAG and UKAS bodies.

If you have any questions regarding our compliance, please call us on FREEFONE 0800 048 1737