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How to Check Water Temperature to Prevent Legionella

Legionella Thermometer - image displays a standard thermometer, used as an example for comparison. Legionella Remedial Works.

How to Check Water Temperature to Prevent Legionella

Legionella bacteria can cause a severe form of pneumonia called Legionnaires’ disease. It spreads when people inhale contaminated water droplets from systems where Legionella is allowed to proliferate. 

Facilities have a legal duty under health and safety regulations to control Legionella risks. A key part of this is regularly checking and maintaining proper water temperatures. 

In this blog post, In this blog post, we’ll explore how to actively monitor water temperature as a crucial preventive measure using Legionella thermometers

Legionella bacteria naturally inhabit water sources but pose a threat when they thrive in human-made systems. Cooling towers, hot water tanks, decorative fountains, and various equipment create ideal conditions for their growth.

Legionella bacteria spread when individuals inhale contaminated aerosol droplets. This transmission can happen through shower sprays, AC systems, humidifiers, equipment hoses, hot tubs, and even garden compost. The bacteria enter the lungs, causing Legionnaires’ disease, a severe form of pneumonia that can be fatal in 10% of cases.

    Why is Managing Water Temperature Critical?

    Water temperature is one of the main factors determining Legionella growth. The bacteria thrive between 20-45°C but are killed at temperatures above 60°C.

    Keeping water outside these ranges prevents growth. Hot water should be stored at least 60°C (or 55°C in healthcare facilities). Cold water should be below 20°C. Stagnation also allows Legionella to multiply, so regular flushing of systems is needed.

    Facilities must comply with UK regulations on Legionella control under the Health and Safety at Work Act. Approved Code of Practice L8 details temperature monitoring and other requirements.

    Why is Managing Water Temperature Critical?

    A specialised thermometer designed for Legionella control makes monitoring water temperatures quick and accurate:

    Legionella Thermometers vs. General Thermometers

    Unlike standard thermometers, Legionella-specific models are designed to provide the accurate measurements needed for water monitoring:

    Narrow precise range from 0-100°C vs. broad -200 to 1000°C range.

    High resolutions like 0.1°C to detect small temperature changes.

    Calibrated and certified accuracy for reliable regulatory compliance.

    Robust waterproof construction to withstand immersion.

    General thermometers lack these specialised features critical for Legionella prevention applications.

    Digital data logger thermometers allow automated 24/7 temperature recording and remote access to data:

    Set up monitoring of multiple water points.

    Data is wirelessly transmitted to cloud servers.

    Review temperature trends and receive alert notifications from any web-enabled device.

    Achieve complete visibility over water systems without manual logging.

    Continuous real-time monitoring ensures the earliest possible detection of any temperature issues.

    What Other Measures Complement Thermometers?

    Along with temperature monitoring, facilities should:

    – Flush infrequently used outlets or equipment before use.

    – Disinfect systems proactively and if Legionella is detected

    – Install copper-silver ionisation treatment.

    – Fitting TMVs in healthcare facilities for safe hot water temperatures.

    – Keep cold water below 20°C and hot stored at 60°C minimum (or 55°C in healthcare).

    Legionella Thermometer - image displays a standard thermometer, used as an example for comparison. Legionella Remedial Works.

    A comprehensive water safety plan incorporates all these strategies. At PTS, we can help you with this – no matter the facility or industry at risk of Legionella. So don’t hesitate to get in contact.

    Ensure Legionella Compliance at Your Facility

    Don’t wait for an outbreak or audit failure – safeguard your water systems now. Installing Legionella thermometers is a simple way to start monitoring Legionella risks. As Legionella Contractors, we know the risks and are experts in preventative measures for businesses, facilities, and landlords or employers across the UK.

    Contact Pipe Testing Solutions today to get expert recommendations on thermometers. We can also provide assistance with legionnaires remedial works and legionella risk assessments for your premises, or facility. Ultimately, maintaining safe water means protecting your occupants – so trust us to handle water safety, and prevent legionella on your behalf.

    Phone: 01922 451646


    Address: Unit 27 Birchbrook Industrial Estate, Shenstone, Lichfield, Staffs, WS14 0DJ

    Our mission revolves around delivering reputable services that ensure water systems’ safety and compliance. Contact us today to discuss your requisites or schedule a consultation. Our knowledgeable team stands ready to assist.


    Kits contain both immersion and surface probes to test all equipment. Having spare probes ensures you always have working thermometers on hand.

    Taps, showers, TMVs if installed, hot tanks, cold water inlet, cooling towers, and other sources or outlets are key.

    Regulations specify frequencies, but best practice is daily for hot water and at least weekly for cold. Log more often when commissioning systems or troubleshooting issues.

    We suggest digital thermometers meeting BS EN 13485. Top brands are Testo, Tricel and Extech. Models with data logging and wireless transmission capabilities are ideal for continuous monitoring.

    Absolutely. Contact us today and our experts can conduct a risk assessment, recommend monitoring equipment, provide staff training, and design a complete water safety plan tailored specifically for your systems and needs.