to be so worried about legionella?

The risk of legionella is small but you should flush your system periodically especially if it's been unused for a while, you just need to turn on all your taps and your shower and let them run for 5-10 minutes.

Pretty much you are being unreasonable to worry about this.

It's very very rare
It's usually caught from buildings like offices, hotels and hospitals not private homes
You don't get it from drinking water even if it is infected

Even if you do get it, it's treatable.

Hopefully this link will put your mind at rest:

https://www.nhs.uk/conditions/legionnaires-disease/

Do you have a combi boiler or cold water tanks and a hot water cylinder?

Your drinking water will be directly from the mains so would be fine.

Bringing the water up to 60C for about an hour would be enough to kill any legionella bacteria.

If you’re still worried, run the taps for a while to get rid of any water that was sitting in the pipes, then give the sinks, baths, taps and shower heads a thorough clean with bleach. You don’t need to do anything more elaborate than that.

Honestly in 4 years of working in acute medicine, never saw it once. And not because we didn't look.

So no, it doesn't make it very likely. It is very very rare.

But does the boiler heat water as you use it or does it heat water and store it in a water cylinder?

The link says you wouldn't catch it from drinking water anyway as its caught by breathing infected droplets. If you're worried run the taps and the shower for a short while to clear the pipes.

This wouldn't even cross my mind. Not even once.

If you're worried, when you move in, turn on the hot water system and then once hot, run the showers for as hot as possible for at least 5 mins. Taps should be OK, but you can do the same again if you want. It's the aerosol (i.e. v small droplets normally associated with showers/air con) that is the problem, so unless your taps have mixers, they shouldn't need it.

You cannot catch legionnaires from drinking water.

It is exclusively transmitted via aerosol, which is why it tends to be in a commercial setting - air conditioning units for example.

It reproduces at an optimum temperature of 40c which is outside the parameters of the temperatures your house will get to. Water heated to 60c or above will kill legionella.

Run all your taps for ten minutes. There you go, you've resolved your potential issue! (Literally - running taps is the key risk management tool when managing a water system as a responsible person).

Also, turning mixer taps as hot as they will go won't help. You need to run the cold water taps and the hot water taps separately to make sure all the water held in any dead legs is flushed out.

H&S Consultant here - you would need to inhale an aerosol of water that contains sufficient legionnella bacteria to make you ill. If you run the taps on full or use a shower you will generate an aerosol. You need to flush the system by turning the taps on to a gentle flow and letting the water run for a while. You need to do both hot and cold systems, and run them for enough time to allow any takes or other ullage to be completely changed.

Sorry to disagree, but you can get legionnella bacteria in sufficiently quanitiy in drinking water to cause legionnaires disease.

Legionella bacteria grow between 20 to 55 C, with the optimum around 40C. Any water stagnant in a pipe that is at 20C or above can have legionella growth. Legionella can and has been found in cold water systems that have been left stagnant where environmental factors have increased water temp to above 20C. That's why we flush both hot and cold outlets in workplace settings.

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Do you know, I've just had a moment of clarity. @LBOCS2 I read your 'drinking water' as in water fit for consumption. Now I realise you meant actually having a drink of water 😜Ignore me...I clearly need more water with tonnes of caffeine in it!

Lol, no worries. Yes, it's in potable water, but you won't get it from drinking it - I could have been clearer too!

running taps is the key risk management tool when managing a water system as a responsible person

Agree. This is what they did in places like hotels and halls of residence which were closed during the pandemic.

It's not anything which would ever cross my mind to be worried about to be honest.

Ant building (or tap) that's been unused for a while should have the taps run for 5-10 minutes when brought back to use and shower heads need cleaning/descaling monthly but there's no need to worry beyond that.

The big risks for legionella are aircon and anything that makes a "mist". Incredibly rare in residential premises.

There are rare cases of people getting it from an old hosepipe that has stagnant warm water in it, WARM being the key.
People died from exposure to an infected hot tub left running in my local JTF, it was room temp so a breeding ground 🤢

As said before, run your boiler at above 60° , run your taps to clear the pipes, maybe if there is a shower hose and head, soak them in a bucket of very hot water and bleach.

@legione just run the hot water into your bath for 10 minutes that'll get the boiler up to temperature providing the dial is set to hive you hot water which I assume it would be if you've been living there for a bit.

You could whack it up to 75° in the boiler controls, which is what DH does when servicing boilers, it’s called ‘chimney sweep mode.