In the light of the recent horrendous flooding as a result of Hurricane Harvey, and now Hurricane Irma hitting the Caribbean, it seems timely to look at the impact of flooding on Legionella risk.
It is increasingly clear that climate change is making the world warmer and wetter, so incidents of flooding are on the rise. Property owners would be advised to put some thought into flood protection and if your home or rental portfolio is at risk of flooding, take this into account when doing your Legionella risk assessment.
Scientists believe that higher rainfall in itself is associated with a greater risk of Legionellosis. When compounded by flooding, the likelihood of Legionella bacteria transferring from the natural environment (rivers and lakes) into domestic plumbing is greatly increased.
Flood water isn’t just water from the natural environment though. It could also contain sewage, toxic waste or other nasties from surrounding buildings or the underground waste water system, so is potentially dangerous and definitely riddled with bacteria. In such situations it is usual to test the water so you know what you’re dealing with and can take suitable precautions when getting rid of the water. You should also be aware of the risk of stagnant water remaining in the property for long periods, perhaps hidden in cavities, dead legs or unseen parts of the plumbing system, as it could harbour Legionella bacteria long after the visible flood water has been cleared.
In one rare case there has even been a situation where a pump used to extract water from a flooded basement contributed to the water heating up (due to the engine working so hard) and the property owner and two other people frequenting the building contracted Legionnaires’ disease from the tepid water.
A severe inundation of flood water into a property can also cause physical damage to the water system by breaking pipes, dislodging water tanks or destroying other plumbing components. If your property has been flooded you’ll need to do a thorough inspection of the system and identify any damage. If you need to have repair work done it makes sense to address any longer-standing Legionella risks at the same time, such as removing dead legs or blind ends, replacing rusty pipework and cleaning water tanks. Once any plumbing repairs are completed, you’ll need to review your risk assessment too, taking into account any alterations to the system. Don’t forget to do a new schematic drawing and take new photographs of the fittings and fixtures as part of your evidence gathering.
It’s clear that flooding can have a major impact on Legionella risk levels, so if you are unlucky enough to have a flooded property, it’s important to take professional advice to help contain, control and reduce the risk quickly. The clean-up operation after a flood is challenging enough, without worrying about the threat of Legionnaires’ disease for both residents and repair workers.
If you own property in a flood risk area or have suffered from flooding, contact us for advice.