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Legionella control case study at a large boarding school

Dantek have provided legionella control services to Marlborough College for a number of years, below is a case study about how we work together to ensure ACoP L8 compliance and the safety of the students and staff.

Since its establishment in 1843 by a group of Church of England clergymen at the Castle Inn at Marlborough, Marlborough College has never been frightened of change. 

In its recent history, numerous academic initiatives have been fostered at the College including, Business Studies, SMP Maths, Combined Science, Pre-U examination syllabuses and the teaching of Arabic and Chinese. In 1968 Marlborough was one of the first of the traditional boys’ boarding schools to admit girls into the Sixth Form.

In 1989, the College became fully co-educational with the admission of girls into the Lower School and with the establishment of the first of the all-girl boarding houses.

Today the College caters for 936 pupils (of which just over 40% are girls) and the great majority of whom (98%) are boarders.  The remaining four “Out-College” houses accommodate 13-16-year-old boys, plus a mixed Sixth Form of both girls and boys.

School size: 201-500 employees

Based at: Marlborough, Wiltshire

The support Dantek provides

As a school, Marlborough College provides care for a large group of students most of which board on site, this means that they must adhere to strict health and safety guidelines. One of these areas is the need to protect students and staff from potential Legionella infection. Dantek has worked with the school for many years ensuring they comply with all regulations thus providing a safe environment for their students to thrive in.

As part of their on-going activity, Dantek engineers monitor the water quality, carry out remedial work and run regular testing and Legionella risk assessments. The College compliance team benefit from using Dantek’s electronic logbook which saves time and helps them keep on top of the various requirements. Dantek has provided a long-standing service to the college and act as part of their team which supports the quality of environment and interaction required by the College.

What does the client say?

We caught up with Kelvin Neale, M&E and Energy Manager at Marlborough College to find out how he views working with Dantek;

How did you hear of Dantek?

I have worked at Marlborough College for 8 months so Dantek were already in place when I joined. However, I did work with Dantek through another employer. I can certainly say that Dantek are known for their sound reputation in the industry.

What are the most important elements you look for in a contractor?

The most important elements for me are timely communication and a conscientious, effective manner. Due to the nature of the work Dantek provide, I also look for clear paperwork and accurate paper trial. We do consider the price, but it is not the only factor. When it comes to compliance, we must make sure we are choosing the right supplier who has the knowledge and systems which we require.

What do you like about working with Dantek?

I am very happy with their work in general. Three things stand up for me in particular:

  1. All engineers are professionals and knowledgeable, DBS checked and employed directly. They will always provide a service that goes beyond their contractual requirements and nothing we ask is ever an issue.
  2. The level of knowledge and expertise the company holds is impressive, they clearly know their stuff. I am also very impressed with the fact that on the rare occasion when they come across something they don’t know; they will go away to research for the right solution. It really demonstrates how competent they are and allows me to trust their advice implicitly.
  3. The electronic logbook is helpful and saves me a lot of time. It means I always have the data I need available to me and we never miss any tests and activities we need to complete.

How do they stand out against the competition?

As mentioned before, Dantek has a strong reputation in the industry. I think the main elements that make them stand out for me are as follows:

  1. The concise and timely completion of every job
  2. The electronic logbook which allows me to stay on top of compliance requirements, documentation and paperwork
  3. The level of knowledge and expertise they demonstrate about water treatment and legionella control


Checking Temperature On A Calorifier

5 key issues to consider about Legionella and care homes

Legionnaires’ disease can cause serious illness and, in some cases, even death if it is not managed correctly.  It is contracted by breathing in droplets of air containing Legionella bacteria.  Legionella bacteria occurs naturally and enters the water system through the mains water supply.  Airborne water droplets are created by water systems such as showers, spa baths, hydrotherapy baths and hot and cold-water services such as spray taps.

While anyone could become infected there are some groups who are more susceptible, and these include the elderly and those with existing underlying health conditions.  Therefore, it is so important for Care Homes to act and put in place a robust management system and practical solutions to protect anyone in their care who may be at risk from the disease.

There are no known cases of Legionnaires’ disease from the natural environment, this is because it is only in man-made water systems where the conditions are right for the bacteria to proliferate.

Earlier this year the private care provider BUPA was fined £3m for failing to prevent and control an outbreak of Legionnaires’ disease when very sadly a resident died. Click on the link below to read more:

Checking temperature on a calorifier
Checking temperature on a calorifier

Where to start?

Controlling legionella in nursing and residential care homes starts with a legionella risk assessment of the hot and cold-water systems to ensure a scheme is put in place to control the risk.  Temperature is the usual method of control with systems operated at the required temperatures to prevent legionella bacteria from growing.  Hot water must be stored at 60°c and distributed at 50°c or higher to all outlets.  Thermostatic mixer valves may need to be fitted at outlets to prevent scalding.  Cold water must be stored and distributed at 20°c.

Regular checks need to be carried out in accordance with the risk assessment, some of these checks can be carried out by your own trained site staff or alternatively you can choose an experienced water hygiene company to do these on your behalf.  Whichever option you choose a key factor for compliance is the management of the control scheme which includes correct record keeping.

Cold water storage tanks must be visually inspected at least every 6 months and cleaned as required. The temperature of stored water must be checked to ensure it is 20°c or less.  Showerheads and hoses must be cleaned and descaled quarterly.   Calorifiers (hot water cylinders) need to be drained and internally cleaned and inspected annually.

It is also important to reduce the possibility of stagnating water in a system, so a risk assessment will identify dead-legs in the pipework which will need to be removed.  Little used outlets which can include showers and taps must be flushed weekly or removed to prevent stagnation.

Electronic log book

Using a cloud-based log book is one of the best ways to keep on top of all the monitoring tasks which need to be performed.  Dantek has developed an easy to use cloud-based system which we provide for free to all our contract customers.  The system ensures all your data for legionella compliance is held in one place and can be reported on and scrutinised, so you know where any problems are and what you need to do to rectify them.  For a short demo of the system please email

5 key points to consider

  1. Do you have an up to date legionella risk assessment and control scheme in place?
  2. Who is the competent person to manage the risks from legionella?
  3. Are your water systems kept clean, with correct temperature controls and no stagnant water?
  4. Are you frequently checking temperatures remain in line with the ACoPL8 HSE guidance?
  5. Do you have accurate records in place to show external agencies?

Dantek is listed on the Legionella Control Association directory of companies who specialise in the prevention and control of legionella bacteria. Do get in touch if you would like to find out more about our legionella prevention and control plans.

Employee profile: David Edwards Legionella Risk Assessor

Legionella L8 assessment
Legionella risk assessing

When did you join Dantek?

I have been working at Dantek for 10 years, I started doing monitoring, tank cleaning, remedial works and cooling tower disinfections. I then progressed into Legionella risk assessing about 5 years ago.  Before joining Dantek, I was at another company cleaning and disinfecting cooling towers and carrying out remedial works on cooling towers as well as tank cleaning and disinfection work. So, by the time I came here as a lead engineer I already had a wealth of experience in the industry.

Becoming a Legionella risk assessor?

Most of my training has been on the job, I started at bottom and have worked my way up by building on experience. I am a qualified plumber so that really helped with my career as it meant I have a solid understanding of how buildings are plumbed and how water systems work. Particularly now as a risk assessor I can easily identifying risk as I know what looking at. I have done every single aspect of water hygiene so can draw on my knowledge when risk assessing a building.

I have spent years of my life stripping cooling towers and working in cooling towers so risk assessing them came very naturally as I have a thorough understanding of how they work.

Of course, I do have formal qualifications in legionella risk assessing but I firmly believe the best way to learn is from practical experience rather than academic study alone.


Where do you start when carrying out a legionella risk assessment?

I tend to start in main plant areas and work my way from there, generally they are the biggest areas of risk. Start with tanks and calorifiers and then move to identifying blinds ends, dead legs and return loops.  I will also request to see any records or previous risk assessment on the building which can be a helpful starting point, although of course it needs to all be updated and schematics drawn to ensure they are accurate, and everything is up to date.


What challenges do you come across?

Cooling towers are challenging, as the legionella risk is potentially so much higher.

Buildings can also be deceptive as a straight forward looking 2 storey building could house any number of systems for example; there could be a lab or have reverse osmosis system, so you need to wait until you discover what is inside.


What work are you most proud of?

Herm Island is definitely my proudest achievement as I have risk assesses every single property on the Island.  All the water is fed from a bore hole, so it has its complications.  I go there every 2 years to update the risk assessments and am so impressed as they have carried out all the recommendations I made in my initial risk assessment. Given they cannot just pop to B&Q as they are an island, they must ship every single part and material in order to do all the remedials, but they have done it all and taken everything on board, which I am afraid to say not everyone does so thoroughly.

I also enjoy going into places and finding tank, calorifiers and even taps that people are unaware they even have.  I am often told there are “no tanks in our building” only to find there were hidden behind a panel or roof space.  It is really satisfying to know you have done a thorough job and being naturally inquisitive has helped me to make sure every tank, calorifer and tap are assessed.


What are the best features of our risk assessment reports?

I think customers find the asset register and photos useful as it clearly sets out exactly what you have on site.  The risk score is also highly valued by customers because it shows what your risk is now and what your projected risk could potentially be if you put in place the control scheme suggested and carry out the remedial work.

We also explain why the risk score has been given with an in-depth explanation for customers. I think this is good because it helps to prioritise where to take action first to make the most impact to reduce the risk on their sites.


What do you enjoy about your job?

I love the freedom of the job and being out and about visiting different places.  I like the trust the responsibility of the job and the satisfaction of knowing the work I do can make a difference by helping to ensure no one suffers with Legionnaires’ disease.


What do you like doing for fun?

I really enjoy sea fishing and try to do as much as I can.  I support Cardiff City both at home and away.  I am currently planning a holiday to Vietnam for next year which will be a great experience and hopefully I will be able to fit in a bit of fishing while I am there.

How much should a Legionella risk assessment cost?


How long does a legionella risk assessment take
How much is a legionella risk assessment?

Your concerned about compliance and you want a good company, but still, budgets are tight, you need the best value, so what do you need to tell contractors to get a fair price? Or get quotes you could compare? And how do these people work it out anyway? I will attempt to throw some light on the occasionally opaque world of Legionella or water risk assessment pricing.

As a start point I have assumed that you are only going to be dealing with reputable contractors who are specialists in the industry, generally members of the Legionella control association, possibly UKAS accredited, who can prove they are competent and have a solid track record. There have been operators in the marketplace who will ‘buy’ risk assessment contracts with the intention of raking the money back on follow-on works and contracts, this is a clear conflict of interest, and I advise avoiding it.

A Legionella risk assessment is a form of consultancy, which means it is, for the most part, a labour only service. This means the big question is – how long is it going to take? Once we figure this out, multiply the time by a day rate and bingo! A price.

Top tip; Ask what the standard day rate is for a surveyor, but be careful, some include administration time some don’t.

Estimating how long a survey will take is a fine art, but there are some variables to consider:


Where is the site? Or where are the sites? Travel time is working time, and you pay for it. Ideally, you’ll use someone local if you have a big single site or cluster of buildings, but sometimes this isn’t practical. If you have many disparate sites, you can get some great economies on a round robin or road trip type basis. Also, these are fun for the surveyors. Years ago, I risk assessed every driving test centre in Scotland on a road trip basis and had a great time.

Once you understand the logistics of getting the surveyor to and from the site, how long will they be there? The two big factors in this debate are; what water services have you got? And how hard will they look? The second point can be contentious, so I’ll deal with what you’ve got first.

Water Assets and system complexity

I have seen many different approaches to convey what is on site, varying from line item asset registers, copies of the previous risk assessments to lists of the gross internal areas of properties. The surveyor’s point of view generally stems from, how difficult is this system going to be for me to understand and how many assets do I have to survey? For example, a large modern office block could seem like a big beast but in reality, may have plant room in the basement, a single wet riser by the lift shaft, toilets and kitchenettes on each floor plus a couple of cleaners cupboards, simple. In contrast, a stately home converted to halls of residence can contain multiple systems and a dog’s breakfast of assets and pipework that would reduce the finest to tears.

Top tip: Give what information you have, including building use, number of stories, and location


The industry refers to all hot and cold-water systems for toilets, sinks, showers etc. as domestic systems. These are almost universally included in risk assessments, but what about cooling towers, industrial uses of water, humidifiers, water features, medical equipment? The survey should cover all water assets one way or another.

In the industry, we benefit from huge amounts of experience so in talking about your buildings we build a picture of what we are dealing with, by being as honest and open as you can you will get the most realistic estimate possible.

The depth of the survey

If you have been on the forums this is a hot potato; the fastidious independent contractors shout down the ‘stack’em high sell it cheap’ brigade for being cowboys and the quick ‘all done on an iPad survey’ crew retort about over-egging the pie. The truth is the risk assessment must be suitable and sufficient, just as the lower the risk, the less you have to do, the converse is also true. There is a place for the iAuditor type surveys on lower risk properties, retail outlets, provincial train stations and minor highways depots etc.

Conversely, if you’re looking after NHS estates, your burden is much greater. The best advice I can give is to view example documents on properties similar to yours, talk to the contractor and understand what they intend to return. You need to feel comfortable the contractor has your best interests front and centre, and they are not ‘flogging you what they’ve got’.

Begin with the end in mind

The Legionella risk assessment certainly ticks a box for compliance but if done well is a tremendous source of information regarding your water assets. Think about practical outputs, for example, how do you expect to see non-compliances reported? Do you want them separated in a way you could pass to a mechanical contractor or your onsite plumbing team?

Talking to your suppliers about Legionella control in a wider context beyond the risk assessment can pay dividends in understanding how the document could support your efforts to implement a successful control regime later on. You’ll be amazed what you can get for free during the risk assessment process just by asking, consider;

  • Do you want accurate schematics drawn in AutoCAD?
  • Would it be handy if the pipe runs are overlaid on your existing building schematics?
  • Would you like an electronic copy of the asset register in excel?
  • Do you want the assets in an electronic logbook as part of the deal?

A word about water samples

There is no hard or prescribed requirement to take microbiological samples during the risk assessment process, in our company we don’t take them as a matter of course but others do. I could write another thousand words on the pros and cons of sampling, but ultimately, to compare quotes you need to understand if they have been included for and if so how many. The current market rate for a Legionella test at a UKAS accredited laboratory is about thirty pounds so cost can be significant if a meaningful number of samples are taken.


At the end of the day

All risk assessment quotes have at their core an estimation of how long the survey is going to take and the report to produce, as a buyer you should understand and be comfortable that your supplier will do a job that is acceptable to you in the time they have quoted. At the bulk end of the market, if you are paying one hundred pounds or less for a risk assessment, your contractor is expecting to do four or more sites per day and is not expecting to find very much. Industry rates vary from three hundred to six hundred pounds per day for a qualified Legionella risk assessor as a guideline.

There are many decent companies out there all of them should welcome sensible discussions on the big question – how long is it going to take?

Dantek are a specialist provider of Legionella control services including Legionella risk assessments.

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