Sigfox helps Cistermiser detect legionella in buildings

  • October 30, 2023
  • Steve Rogerson

European Sigfox operator Heliot is working with Cistermiser to improve legionella detection in offices, hospitals, care homes, restaurants and stadia.

UK firm Cistermiser’s LinkThru temperature monitoring units (TMUs) have been designed to connect to Heliot’s Sigfox-0G network. They are used by building owners, facilities managers or maintenance professionals to monitor water flow and temperature in water systems, in an effort to reduce the risk of legionella.

Installing 250 TMUs within a water monitoring system can save organisations 27,000 litres of water and around £225 per year.

Established over 40 years ago, Cistermiser is a manufacturer and supplier of products for the treatment and management of water. Its LinkThru TMUs are compact, easy-to-install and scalable, and have been designed to connect to a cloud-based reporting and alert system. They replace traditional resource intensive approaches to legionella risk management, and automate the process and reporting required to mitigate the risk of legionella.

The TMUs have been designed in collaboration with Heliot and Spica Technologies. TMU connectivity is handled by Heliot’s Sigfox network. Spica enables data captured by the TMUs to be configured into the appropriate required reports and alerts that let organisations adhere to HSE technical guidance and approved codes of practice.

“The issue of legionella is increasingly in the news and is problematic,” said Richard Braid, managing director of Cistermiser. “Traditional methods of water outlet and sentinel temperature monitoring associated with reducing the risk of legionella are resource intensive, manual, costly and prone to error. What is more, managing the electronic log book that is required to demonstrate legionella compliance is difficult with current traditional paper-based systems. LinkThru has been designed to meet this challenge.”

Once the TMUs are connected to pipework systems, they harness IoT technology and connectivity to monitor water temperature and flow, and the data captured are reported in an appropriate format for regulators. This enables building owners to ensure compliance with HSG274 regulation so they can reduce the risk of legionella and other waterborne pathogens.

“Since our LinkThru TMUs are often fitted in remote locations, we needed to ensure that we developed an effective network to connect our devices to,” said Braid. “We considered SIM cards and cellular networks and wifi, but the reality is that these were not cost effective for our devices, nor were they as reliable. Instead, we explored the use of Sigfox and sub-gigahertz network technology, and settled on that for a number of reasons. Sigfox is ubiquitous, robust and reliable across the UK and Europe. When this form of connectivity is integrated into our devices it enables reach into areas that other networks cannot access.”

This includes underground locations or in concrete buildings, which is where many water systems are located. Connecting the devices to a Sigfox network enables the transmission of small packets of data, helping ensure battery power on devices is not compromised, meaning devices can last in the field for longer.

“Using Sigfox connectivity is more appealing to IT and security teams, as it means that devices do not need access to clients’ networks, wifi or security systems, so, installers, facilities managers and building managers can fit TMU devices easily to set up a legionella management system, and start drawing insights in real time rapidly,” said Braid.

Heliot is the exclusive operator of the global Sigfox 0G network in Germany, Switzerland, Austria, Slovenia, UK, Denmark and Liechtenstein. This makes it the largest 0G network operator in Europe. With Sigfox technology, Heliot offers a cross-border, seamless, user-friendly, cost-effective and energy-efficient network and helps companies transform their business model towards digital services in areas such as asset tracking, asset monitoring and supply chain management. Low-frequency radio technology can also be a cost-effective alternative to the existing NB-IoT and Cat-M.

“Cistermiser is a true industry leader in its field,” said Gareth Mitchell, partner manager at Heliot Europe. “It has reviewed the market and developed IoT-based devices to improve operational efficiencies within the water management sector. Its LinkThru devices, connected to the internet of things via our sub-gigahertz Sigfox network, enables organisations to improve how they run legionella risk management operations. Moreover, this is a proven example of how Sigfox can drive reliable connectivity across IoT devices and applications, where other forms of connectivity cannot succeed.”

Heliot ( also offers access to its global Sigfox 0G ecosystem with almost 1000 sensors and analysis tools for collecting and evaluating their data.

Cistermiser ( has been manufacturing and supplying products for the treatment and management of water for over 40 years. It designs, manufactures and sells washroom control products including water saving and efficient hydraulic and infra-red urinal flush control valves, hands-free hygienic no-touch WC flushing valves and touchless infra-red washbasin taps for industry, the public sector, and commercial and domestic applications.