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Legionella Temperature Monitoring

Hold the line.
20C to 45C.
Around the clock.

Legionella proliferates in the 20C to 45C window. AQUAIOT profiles temperature continuously at tanks, calorifiers, and outlets, so you see the drift a monthly spot reading never catches.

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Live monitoring. Continuous compliance.
AQUAIOT L8 Dashboard
42Outlets OK
3Caution
1Alert
Sentinel Outlets – Live
Tank A – Cold Feed18.4°COK
Outlet 7 – HWS Return49.1°CCaution
Outlet 12 – Sentinel56.8°CAlert
CW Tank B17.2°COK
Man-in-a-van visits leave gapsInspection sheets capture one moment. Between rounds, temperatures drift unseen, and your compliance record has no answer for it.
Legionella thrives between 20C and 45CRisk conditions develop and resolve between visits. Manual schedules cannot catch what happens overnight.
Audit prep should not take daysWhen an inspector asks for records, paper logbooks take days to compile. A digital audit trail is instant.
Every missed flush is a duty-of-care gapOne undocumented flushing event is a defensible record waiting to fail under legal scrutiny.
The AQUAIOT Solution

Continuous profiling.
Not a monthly
snapshot.

A spot reading tells you one temperature at one moment. AQUAIOT records the full temperature profile across the day and night, so the proliferation window is never invisible.

Continuous temperature profiling, every reading timestamped and logged at tanks, loops, and sentinel outlets, not one figure on a monthly clipboard.
Alerts on the danger window, immediate SMS, email, and app notification when cold water rises above 20C or hot water falls below the expected range.
The whole curve, not a dot, trendlines reveal overnight drift, stagnation, and recovery that a single periodic reading simply cannot show.
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Live Outlet Status
CW Tank – Return Temp16.8°C
HWS Flow – Calorifier60.4°C
HWS Return – Loop 349.3°C
Sentinel Outlet 1256.8°C
Alert triggered – Outlet 12
Temperature above L8 calorifier threshold. Notification sent 14:32.
How It Works

Three steps to continuous L8 compliance

Step 01

Monitor

AQUAIOT sensors are deployed at tanks, loops, calorifiers, and sentinel outlets. Temperature is profiled continuously, every reading timestamped and logged to the cloud over secure cellular or LoRaWAN telemetry.

Step 02

Alert

When temperatures drift outside HSE L8 thresholds, or when a scheduled flush is missed, AQUAIOT triggers an immediate alert via SMS, email, or app, with role-based escalation rules for your estates team.

Step 03

Record

Every reading, alert, and action is captured in tamper-evident audit logs. Records are exportable on demand and integrate with CAFM, BMS, and AIMS systems, so audit preparation is minutes, not days.

Capabilities

Everything your L8 programme needs

Purpose-built for estates, facilities, and compliance teams managing water systems across single or multiple sites.

Real-time temperature profiling

Continuous monitoring at tanks, calorifiers, loops, and sentinel outlets. Every reading timestamped and stored, never a gap in your record.

HSE L8 threshold alerting

Thresholds checked against HSE L8 and ACoP guidance. Alerts fired immediately when cold water exceeds 20C or hot water falls below 50C at point of use.

Missed-flush detection

AQUAIOT detects when scheduled flushing routines are not completed and generates an automatic alert, so no event is undocumented.

Tamper-evident audit trails

Every reading and action is logged with a secure, unalterable timestamp. Exportable records ready for audit, inspection, or HSE enquiry at any time.

API / BMS / CAFM integration

Open and interoperable. AQUAIOT connects to your existing SCADA, AIMS, CAFM, and BMS platforms via RS485/Modbus or REST API, no lock-in.

Retrofit-friendly deployment

Non-invasive sensors designed for live environments. No pipe cutting, no shutdown. AQUAIOT engineers handle site survey, installation, and commissioning.

Compliance & Standards

Aligned to the standards your auditors check.

HSE L8 & HSG274 Part 2 20C to 45C Risk Window Continuous Profiling Timestamped Trendlines
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No commitment. Talk to our engineering team.

Who It’s For

Built for the teams responsible

Housing Providers

Protect tenants. Prove compliance.

Housing associations and registered providers carry a statutory duty of care over water systems in their properties. Manual L8 management across multiple sites is operationally fragile, and increasingly under scrutiny.

  • Continuous monitoring across all properties, single dashboard view
  • Automatic alerts when vacant properties develop risk conditions
  • Audit-ready records for insurance, regulatory, and legal purposes
  • CAFM and property management system integration
NHS & Public Sector

Clinical-grade water safety. Without the admin burden.

NHS Estates and public sector facilities operate under HTM 04-01 and HSE L8 obligations. The complexity of large estates, multiple buildings, and dense pipework makes manual monitoring inadequate at scale.

  • Dense outlet coverage across clinical environments
  • Real-time temperature monitoring at thermostatic mixing valves and outlets
  • Integration with existing BMS and CAFM infrastructure
  • Automated compliance records compatible with HTM 04-01 requirements
Facilities & Estates

Less time on rounds. More time on management.

Commercial estates, universities, leisure facilities, and large offices face the same challenge: manual L8 inspection rounds are resource-intensive and provide only a snapshot. Automation changes that calculus entirely.

  • Replace labour-intensive manual rounds with automated monitoring
  • Role-based dashboard access for estates managers, deputies, and contractors
  • Reduce reactive call-outs, detect issues before they escalate
  • On-demand compliance reports for building managers and insurers
Defence & Secure Sites

Secure by design. Compliant by default.

Defence estates, MoD sites, and government facilities carry the same L8 duty of care as any other property, often across aging, complex pipework that is hard to reach and harder to document. Manual rounds leave gaps AQUAIOT closes permanently.

  • Encrypted telemetry, cellular and LoRaWAN with secure payload transmission
  • Tamper-evident immutable logs with timestamps and user actions
  • Role-based dashboard access, right records to the right people
  • Auditable compliance records meeting MoD and government estate requirements
Open, interoperable systems. No lock-in. Engineered for operational environments.
Cellular + LoRaWAN telemetry Encrypted payloads & OTA updates RS485/Modbus + REST API Role-based cloud dashboards CAFM / BMS compatible
Questions & Answers

Legionella temperature monitoring, answered

What temperature range does Legionella proliferate in?
Legionella bacteria multiply most readily in stagnant water roughly between 20C and 45C. The control principle in HSE guidance is to keep cold water below 20C and hot water hot enough to suppress growth. Continuous monitoring shows whether your system actually holds those conditions, rather than assuming it does between readings.
Why is continuous monitoring better than a monthly spot reading?
A monthly reading captures one temperature at one moment, usually during the working day. It cannot see overnight warming, weekend stagnation, or short drifts that resolve before the next round. AQUAIOT profiles temperature continuously, so the full curve, including the hours nobody is on site, is recorded and checked against thresholds.
What temperatures should cold and hot water hold?
Under HSE guidance the broad targets are cold water below 20C and hot water stored and circulated hot enough to control growth, with sentinel checks confirming flow and return. AQUAIOT lets you set thresholds for each asset and alerts you the moment a reading moves outside the band you have configured. Your duty holder sets the control regime; the system evidences it.
Where are the temperature sensors placed?
Sensors are fitted at cold water storage tanks, calorifier flow and return, hot water circulating loops, thermostatic mixing valves, and sentinel outlets. These are the points where temperature reveals whether the system is in control, and where continuous profiling adds the most value.
Can I see historical temperature trends?
Yes. Every reading is logged with a secure timestamp, building trendlines you can review on demand. This makes it straightforward to spot a slow drift, confirm a corrective action worked, or produce a continuous record for an audit, rather than reconstructing the picture from sparse manual entries.
Explore the AQUAIOT range

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Automated Legionella Monitoring Wireless Legionella Sensors Continuous Legionella Monitoring Legionella Compliance Monitoring Cold Water Storage Tank Temperature Monitoring Legionella Monitoring for Care Homes
Ready when you are

Stop guessing what happens between readings.

Talk to our engineering team about continuous temperature profiling and threshold alerts across your water system.

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Legionella Temperature Monitoring – Speak to an AQUAIOT engineer about your estate.
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