The water that is dispensed from a properly maintained and sensibly used water cooler should be of the same quality as the water before it enters the cooler or filter. To put it another way, the Water Cooler should not contribute in any way the microbiological content of the water.
EPDWA guidelines state that all bottled water coolers should be sanitised on a quarterly basis and mains-connected coolers should be sanitised and filters replaced 6-monthly. After the recommended sanitisation period has elapsed water quality will begin to deteriorate, although the water will still be fit for consumption.
Sanitisation is the cleaning and sterilisation of the water contact parts of a water cooler and especially the tap mechanism. It is designed to remove biofilm and other bacterial matter from the Water Cooler. Biofilm is organic matter which contains bacteria and can build up on the water contact surfaces of both bottled and plumbed-in water coolers.
In bottled water coolers, the main sources for contamination is when bottles are loaded/unloaded or from careless tap handling.
As mentioned above with regards to Dispense tap sanitisation.
We have had a small number of clients approach us as they have, as part of their normal health and safety processes, had their mains and water cooler water tested for microbiological content or Total Viable Count (TVC). The chlorinated water coming from your mains taps will usually have a TVC count of less than 100 cfu per ml. The TVC of water dispensed from a bottled or mains-fed water cooler is likely to be significantly higher due to the lack of chlorine. This does not normally mean that it is unsafe to drink, indeed a recent TVC count of 10,000 from an On-Tap client, was considered by the EPDWA’s resident.