Our engineers inspect thousands of rental properties every year to carry out Legionella risk assessments, so they see an enormous variety of houses and plumbing systems. This week we’ve been speaking to Sam, one of our engineers, about the most common problems he finds.

1. Lack of understanding by tenants

“Many of the properties I visit are social housing accommodation and very often the tenants have no understanding of why the risk assessment is important. I always explain what I’m there for and why I’m doing the risk assessment but the more that landlords can do to inform and educate tenants about Legionella control, the better. After all, it’s being done to protect them and their family! Tenants can also help with things like regular descaling and reporting plumbing problems to the landlord, so keeping them on-side and informed is really important.”

2. Limescale

“The majority of the properties I cover are in hard water areas so we see a lot of limescale build-up on taps and showers. Limescale is relatively low risk for Legionella, but nonetheless it should be kept under control with regular descaling as otherwise it can be a food source for Legionella.”

3. Dirty water tanks

“The larger blocks of flats which I inspect generally have a large shared tank, which is usually in good condition, but where there are smaller blocks or houses, it’s frequently the case that I’m the first person to have gone into the loft to look at the tank since it was installed – often decades before! An ill-fitting lid, or no lid at all, means the water can be very dirty with lots of sediment, biofilm and limescale in the tank. Sometimes the pipes are corroded too. Poor insulation can also mean that the temperature of the stored water isn’t at the right temperature, which also increases the risk of Legionella.”

4. Inadequate hot water temperature

“We very often find that the hot water isn’t hot enough to kill off Legionella. It needs to be 60°C but because of incorrect thermostat settings, poorly maintained boilers or sometimes the tenant trying to save money by not topping up the electricity or gas meters, we find several properties a day where the water isn’t sufficiently hot. This is a really important problem to address as it’s a key control measure for Legionella so we always mark it as a high priority in our report.”

5. Dangerous douches and showers

“Many properties I visit are occupied by tenants with different cultural backgrounds, which can include religious or traditional practices such as douching. They may have installed a douche themselves in the bathroom – perhaps without the permission or knowledge of the landlord – which doesn’t comply with water regulations so there’s a high risk of backflow of dirty toileting water into the plumbing system. Alternatively, the shower may have been tampered with so that it will reach the toilet, which also contravenes water safety regulations. Where douches are required, it’s very important that they are installed properly with backflow prevention measures.”

So what would Sam’s top tips be for simple Legionella control measures for landlords and managing agents to implement?

1. Check water temperatures regularly, in particular making sure that the hot water is over 60°C.
2. Inspect the water tank annually, checking that the insulation and lid are in good condition, the water clean and at the right temperature.
3. When you do your risk assessment remember to check for any places where water can collect and stagnate e.g. deadlegs or long, horizontal runs of pipe. Stagnant water is a high risk for Legionella but it’s relatively simple to prevent it from becoming a problem by checking your pipework is in good order.