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Legionella Monitoring Guidelines

Monitoring Guidelines | Water Logbook | Legionella Monitoring

Legionella Monitoring Guidelines


Here you will be given an introduction to the monitoring tasks and requirements to be completed. Good practice will have you complete a legionella risk assessment first, followed by the remedial works to lower the risks identified. Thereafter, ongoing monitoring and maintenance must be carried out (legionella monitoring).

Weekly Tasks

Flushing Infrequently Used Outlets

Consideration should be given to removing infrequently used showers, taps and any associated equipment that uses water. If removed, any redundant supply pipework should be cut back as far as possible to a common supply (e.g., to the recirculating pipework or the pipework supplying a more frequently used upstream fitting) but preferably by removing the feeding ‘T’. Infrequently used equipment within a water system (i.e., not used for a period equal to or greater than seven days) should be included on the flushing regime.

Flush the outlets until the temperature at the outlet stabilises and is comparable to supply water and purge to drain. Regularly use the outlets to minimise the risk from microbial growth in the peripheral parts of the water system, sustain and log this procedure once started. For high-risk populations, eg healthcare and care homes, more frequent flushing may be required as indicated by the risk assessment

Water Softener Level Checks

Visually check the salt levels and top up salt, if required. Undertake a hardness check to confirm operation of the softener

Changeover Pumps

Changeover pumps to be alternated weekly to avoid stagnation on one pump

Monthly Tasks

Cylinder Temperatures

Check calorifier flow temperatures (thermostat settings should modulate as close to 60 °C as practicable without going below 60 °C). Check calorifier return temperatures (not below 50 °C, in healthcare premises not below 55 °C)

Combination Water Heater Temperatures

Check water temperatures at an outlet to confirm the heater operates at 50–60°C

Hot Water Services Temperatures

For non-circulating systems: take temperatures at sentinel points (nearest outlet, furthest outlet, and long branches to outlets) to confirm they are at a minimum of 50 °C within one minute (55 °C in healthcare premises)

For circulating systems: take temperatures at return legs of principal loops (sentinel points) to confirm they are at a minimum of 50 °C (55 °C in healthcare premises). Temperature measurements may be taken on the surface of metallic pipework.

For circulating systems: take temperatures at return legs of subordinate loops, temperature measurements can be taken on the surface of pipes, but where this is not practicable, the temperature of water from the last outlet on each loop may be measured and this should be greater than 50 °C within one minute of running (55 °C in healthcare premises). If the temperature rise is slow, it should be confirmed that the outlet is on a long leg and not that the flow and return has failed in that local area. This should be undertaken quarterly (ideally on a rolling monthly rota)

Cold Water Service Temperatures

Check temperatures at sentinel taps (typically those nearest to and furthest from the cold tank but may also include other key locations on long branches to zones or floor levels). These outlets should be below 20 °C within two minutes of running the cold tap. To identify any local heat gain, which might not be apparent after one minute, observe the thermometer reading during flushing

Quarterly Tasks

Dismantle, Clean, Descale and Disinfect

Showers and spray taps (advised all taps) – dismantle, clean and descale removable parts, heads, inserts and hoses where fitted

Re-Circulating Return Loop Temperatures

Record temperatures of return loops on the hot water system. In larger water systems, hot water cylinders have a flow and return. The hot water flows from the cylinder through the pipework and returns back to the cylinder where the hot water is then pumped back around in through a re-circulating loop of pipework, in effect like a racing track leading you back to the start. When this happens, there are subordinate loops, or loops that are added to the circuit. These loops must be tested for their temperature quarterly to ensure temperates remain within the compliant range.

Six Monthly Tasks

Expansion Vessel Flushing

Where practical, flush through and purge to drain. Bladders should be changed according to manufacturer’s guidelines or as indicated by the risk assessment. Monthly-six monthly as per guidelines.

Filter Service

Service as per manufacturers guidelines. Filters naturally collect debris and dirt within the water system. This means filters are prone to clogging up and harbouring harmful bacteria.

Annually Tasks

Review (Risk Assessment, Logbook And Remedials)

Arrangements to review the risk assessment regularly and particularly when there is reason to suspect it is no longer valid

Cold Water Storage Tank Inspection

Inspect cold water storage tanks and carry out remedial work where necessary

Cold Water Storage Tank Temperatures

Check the tank water temperature with a legionella thermometer, remote from the ball valve and the incoming mains temperature. Record the maximum temperatures of the stored and supply water recorded by fixed maximum/minimum thermometers where fitted

Cylinder Inspection

Inspect calorifier internally by removing the inspection hatch or using a boroscope and clean by draining the vessel. The frequency of inspection and cleaning should be subject to the findings and increased or decreased based on conditions recorded.

Where there is no inspection hatch, purge any debris in the base of the calorifier to a suitable drain. Collect the initial flush from the base of hot water heaters to inspect clarity, quantity of debris, and temperature

Combination Water Heater Inspection

Inspect the integral cold water header tanks as part of the cold-water storage tank inspection regime, clean and disinfect as necessary. If evidence shows that the unit regularly overflows hot water into the integral cold water header tank, instigate a temperature monitoring regime to determine the frequency and take precautionary measures as determined by the findings of this monitoring regime

TMV Service

Where needed, inspect, clean, descale and disinfect any strainers or filters associated with TMVs. To maintain protection against scald risk, TMVs require regular routine maintenance carried out by competent persons in accordance with the manufacturer’s instructions. Tasks include temperature calibration, failsafe testing and clean, descale and disinfect strainers or filters

Representative Temperatures

Hot water services

All HWS systems: take temperatures at a representative selection of other points (intermediate outlets of single pipe systems and tertiary loops in circulating systems) to confirm they are at a minimum of 50 °C (55 °C in healthcare premises) to create a temperature profile of the whole system over a defined time

Cold water services

Take temperatures at a representative selection of other points to confirm they are below 20 °C to create a temperature profile of the whole system over a defined time. Peak temperatures or any temperatures that are slow to fall should be an indicator of a localised problem

Water Softener Service and Disinfection

Service as per manufacturers guidelines

Legionella Sampling

As per BSI standards publication for legionella sampling BS 7592 2008 – Sample for legionella – bacteria in water systems – code of practice

Other Risk Systems

For guidelines references please see – HSG 274 part 3 (appendix 3.1 checklist for recommended frequency of inspection for other risk systems – pages 5-7)

Download the HSE’s HSG 274 Part 2 Legionella Guidelines for FREE


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We have been working with Urisk for best part of year now. I could not recomend their services highly enough. They always promptly respond to our requests promptly and manage the job from start to finish seamlessly. I would highly recommend.
Sam Guest
Sam G.
My first time using Urisk for work at multiple sites. Daniel was absolutely brilliant, polite and professional. Highly recommended! 🙂
Claire Keay
Claire K.
Fantastic training courses and we've found the legionella risk assessment very easy to read and far more detailed than any we have previously had. 5 star service!
Gemma Pond
Gemma P.
Incredibly detailed and professional team. Have been beyond helpful with with our CQC legionella compliance for our Safety. They’ve found solutions to fit around how we work and our budgets. We are always advised with reference to HSE which has been brilliant.
Amy Thorne
Amy T.
Really easy to organise a risk assessment to be carried out at our offices and have had great help from them since to implement the necessary changes to keep the office safe. Would definitely recommend.
Holly Ferguson
Holly F.
Brilliant Service, efficient, professional, punctual and friendly.
Alex Windsor
Alex W.
We're a small GP practice and started using uRisk for legionella risk assessments. We opted to use their remedial and monitoring services and they've been absolutely great. We cannot recommend them enough! Thank you so much!
Amanda Pates
Amanda P.
Brilliant company, customer service was great! And engineers were fantastic. Thanks again uRisk! Will definitely be using them for all future work.
Nikesh Gohil
Nikesh G.
uRisk have been helping us with our Legionella Control for a number of years now. We've recently had a CQC audit and they were very impressed with our legionella compliance! Thank you for all your help.
Mike Port
Mike P.
Brilliant service! Thanks a lot for the hard graft
Leon Macauley
Leon M.
Daniel did the testing today at PGHC He was really efficient, friendly and so professional. An absolute pleasure to deal with. Thanks Daniel
Lorraine Carruthers
Lorraine C.
My experience with URisk Water Hygiene from my initial enquiry, to their site visit to undertake a Legionella Water Risk Assessment at my office (MDG), to providing me with the report and aftercare has been superb! Efficient response times, excellent customer service, friendly, helpful advisors and assessors who are always ready to help and provide guidance. An absolute pleasure to deal with, I highly recommend!
Lauren Wakeman
Lauren W.
A fabulous company, excellent customer service, they try to accommodate appoitments, and do there utmost in emergencies, been with them a few years now,  honestly cant fault them. Coming out of Covid 19, having our building urgently disanitised,  big thank-you to Luke and Lee for staying so late to get the job done!! Thank you Devon, for juggling the diary to fit us in so soon. A Team 🙂
Jo Maskell
Jo M.
Richard & Nick are great. Really good work and nice people.
Joshua Ballard
Joshua B.
This is by far the best service I have received in a long time.Lloyd who we spoke to was super helpful and very thorough with everything.I would def recommend using this company, they are not just out for money they put their customers needs first.Thank you
Coral Dawkins
Coral D.
Extremely happy with our legionella risk assessment carried out by uRisk, easy to understand and great customer service. Thanks again
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Nickayla R.

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