Legionnaires risk assessment when letting

warthog_78

I've been told today that it's now compulsory for landlords to do legionnaires risk assessments. After a quick google on HSE it sounds right. I wasn't aware of this until now. Any advice on how to do this without getting fleeced?

Owain_Moneysaver

Follow the guidelines at

http://www.hse.gov.uk/legionnaires/faqs.htm#Landlord

and document it.

And provided you have an ordinary domestic hot water system, well-fitting lids on any tanks in the loft, and sufficiently hot water in the hot water cylinder, you should have no problems.

patman99

The tests are easy to do. You will need a temperature sensor with both a probe and a clamp if you want to make the job easier.

The main things to remember are -

1. All hot water to taps should be above 65 deg. C
2. All cold water to taps should be below 20 deg. C

Make sure to run taps for a few minutes to flush out the pipes prior to testing and keep the taps running during the test as well.

If you have TMVs (Temperature Moderating Valve) then the hot water must be measured BEFORE the TMV. You can also log the temperature of the water exiting the tap to prove that the TMV is correctly set, but this is not part of the legionaire test.

It is worth noting that if the property is to be left vacant for a while, then it is recommended that every tap and shower is run for 5 minutes each week to flush the system.

Marktheshark

No dead ends on hot water pipework as well, old tap feeds , unused washer feeds on spurs, all best capped off so the feed is boiler to taps only.

martindow

Is Legionnaires really a risk in a domestic hot water system? I understood that cases usually involved badly maintained air conditioning units.

This sounds like a scare story from people offering to perform tests (and making money).

Edit: Although the HSE link suggests LL should jump through these hoops, has anyone worried about this in their own house?

maninthestreet

Not worried at all - what about the risk of scalding from hot water at 65c ???

Malibusmash

Is this actually a legal requirement? Does the LL need to provide proof of testing to the Tenant?

RAS

In most residential settings, a simple assessment may show that the risks are low and no further action may be necessary. (An example of a typical lower risk situation may be found in a small building (eg housing unit) with small domestic-type water systems, where daily water usage is inevitable and sufficient to turn over the entire system; where cold water is directly from a wholesome mains supply (no stored water tanks); where hot water is fed from instantaneous heaters or low volume water heaters (supplying outlets at 50 °C); and where the only outlets are toilets and wash hand basins). If the assessment shows the risks are low and are being properly managed, no further action is needed but it is important to review the assessment regularly in case anything changes in the system.

So as a LL if you assess your properties against the criteria above, you should be OK. Just record your assessment

You might want to ask more searching questions of the management company if you own a flat that has shared heating systems or shared water storage.

Fluff15

martindow wrote: »

Is Legionnaires really a risk in a domestic hot water system? I understood that cases usually involved badly maintained air conditioning units.

This sounds like a scare story from people offering to perform tests (and making money).

Edit: Although the HSE link suggests LL should jump through these hoops, has anyone worried about this in their own house?

Generally, most AC is air to air, and therefore legionella will not be found in an AC system because there is no water. But it can be found in water cooled AC systems, as well as heating systems, cold water systems, showers etc.

The most likely place you will find legionella bacteria is in dead legs of water systems and your car windscreen washer tank if you've ever filled it up with just water. Schools and the suchlikes tend to need flushing regimes in their shower blocks where the kids don't use the showers.

A small domestic system will probably be free of legionella as long as there's no dead legs, and the hot water is over 50 (official recommends 60, but as a contractor we have never found it above 50).

natrapx

Legionella risk assessor chiming in on this.

Whilst I've done a couple of council houses (one's where the council or agency lets them out to a tenant in need, not just general housing stock) I've never done a private residence. The risk will generally be low on private residences as all the water services will be in constant use. The more tricky situations occur when a building has been not-occupied.

General guidance for a domestic system would be thus.

65C is too hot for a domestic system. General rule of thumb is stored water at 60, water to the outlet at greater than 50. Dead-legs are an issue if you have them, but as its a residential property, if there are any they will be minor. Get a qualified plumber to do a quick look around and remove any that come up if that worries you or its an older house.

Showers, if they are electric, take the head off and run at >60C for a period of no less than 5 minutes. If they are fed from your heating system directly, put the temperature up to >60C and flush every outlet, including the shower, for 5 minutes. Make sure you have the shower head/hose cleaned before they move in, to clean out any gunk in the hose or head.

If the house is not occupied for more than a week, run every outlet, again for 5 minutes just to purge any dead water. Problems occur primarily with stagnant water, so just minimise that, keep cold temperatures below 20 and hot above 50 and you should be fine.

If there is a cold water storage tank in the roof, I'd suggest having a look at it, and if its in a bad condition, get it replaced with a direct mains supply. You're looking for areas that bugs or insects can crawl in, making sure its insulated, no corrosion and little to no sedimentation at the bottom of the tank.

Feel free to PM me if you have any direct questions regarding this area.

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I take no responsibility for the advice given. Read up on this further, or arrange to speak to someone directly regarding legionella to suit your property.

Hoploz

My plumber happened to mention legionnaires today when discussing hot water temps! Never crossed my mind until now! He also said in new builds the water must come out at 48 degrees I think he said ... That seems a long way from 65 in the tank. I have always turned down thermostats on my cylinders to below 60 degrees to prevent scalding! He mentioned the tank must be hot enough to kill legionnaires off. Sorry, nothing to add, just interested as it came up for first time ever today.