Last week we visited a hotel in Birmingham to carry out the water sampling which their legionella risk assessment recommended. The hotel has one large cold water storage tank which feeds all cold outlets in all accommodation rooms and feeds 2 water heaters which provide hot water.
The hotel had 35 showers which were also fed by these water services. According to the hotel manager, this was the first time they had had the water sampled. Also, since the water systems were fitted 4 years ago, the cold water storage tank had never been clean and chlorinated.
Water sampling of such a water system should usually be carried out annually (but your legionella risk assessment will give the exact requirements for your system). Both Legionella water samples and TVC (Total Viable Count) water samples should be taken from the cold water storage tank itself and from the furthest ‘tank fed’ outlets (these are called the ‘sentinel outlets’ of the tanked cold water system). The same types of samples should be taken from the base of each water heater and from the furthest hot outlets away from each water heater (these are called the ‘sentinel outlets’ of the hot water system).
Total Viable Count samples analyse water for the numbers of ‘living organisms’ – either bacteria, yeast or mould. When our UKAS Accredited laboratory analysed the water samples, the TVC samples were all unsatisfactory, all showing over 1000 cfu/ml (colony forming units per millilitre).
