How many Legionella samples should I take?
To answer that question there are a number of factors to take into account. The main two factors are:
- How many different water systems you have.
- The size of your facility.
How many different water systems you have, typically most sites have 2 systems, 1 x cold water and 1 x hot water system. But if you have rainwater catchment that might be being used for watering of gardens or flushing of toilets, well you now have 3 systems that require testing.
Depending on how your facility was built you may have multiple separate hot water systems, each different hot water system is a system that is required to be tested. If you have a new part or recently built extension to your facility and you have a warm water system instead of a hot water system, there is another system that requires testing.
So how many Legionella samples should you take now? Well, let us look at the other main factor.
According to the Guidelines for Legionella control in the operation and maintenance of water distribution systems in health and aged care guidelines (pg31) states that sampling should be at a ‘building, department or ward’ level. So if you have a facility that has multiple buildings, multi-story buildings and building that have lots of branch lines (distal points) you will have to consider taking a sample for each and everyone of those factors.
So how many water samples do you have to take now? As you can see the answer is not as simple as one sample per 5 or 10 rooms. Let’s look at a couple of other factors that may contribute to how many samples you need to take.
The age of a building, generally the age of a building which has had repair work or refurbishments can generally be susceptible to Legionella due to dead legs or little used outlets and you may have to increase your sampling in that building for a high level of vigilance.
The residents of the building they might be bed bound or sponged bathed and they may have a higher risk and be susceptible to Legionella so it might be prudent to test more frequently than the industry minimum standard of every three months.
Compliance Water Services with its knowledge and expertise when implementing a Water Risk Management Plan for a facility understands that the on-going sampling will end up being the most expensive cost in the long run. We strive to optimise the sampling by taking into consideration the above factors and more to give you the best value for money sampling programme without compromising on safety.
