Legionella compliance
for Dubai buildings.

TL;DR

• DM-HSD-GU44-LCWS2 V6 (19 August 2025) applies to hot, warm and cold water systems, cooling towers, fountains, water features, spas and irrigation storage — in practice, any building with a tank, a calorifier or a tower.
• Temperature is the primary control: hot water stored at 60 °C, at least 50 °C at outlets after one minute, hot/warm systems held at 50–60 °C at all times, cold water below 20 °C at all times. The bacteria multiply at 20–45 °C.
• Laboratory cultures are quarterly (ISO 11731, EIAC-accredited labs), aerobic counts monthly for cooling towers. Exceedances trigger prescribed action ladders — the top rung for a cooling tower is "turn the tower off".
• The paperwork is the hidden cost: daily temperature and disinfectant records at four or more locations, a twelve-task maintenance calendar, eight categories of documentation held for inspection — and record forms submitted to [email protected] every two weeks, plus weekly portal updates.
• Honest scope: GU44 does not mandate IoT or continuous monitoring — the words do not appear in the document. Continuous temperature sensing is how you catch violations between quarterly cultures and generate the records automatically, not a legal requirement in itself.

1. Who this applies to

The guideline's scope is defined by equipment, not by industry. If a building in Dubai has any of the following, GU44 applies to it:

• Water storage tanks or cisterns (sampling required on the main tank and every tank over 1,000 litres)
• Centralised water heaters / calorifiers
• Cooling towers or evaporative condensers
• Fountains, waterfalls, decorative water features
• Spas, jacuzzis, whirlpools
• Irrigation storage tanks

That covers offices, malls, hotels, schools, hospitals, mosques, residential towers and labour accommodation — the last of these by explicit cross-reference in DM-HSD-GU85, which folds GU44 into a single multi-system compliance load for worker housing.

2. The temperature regime

Legionella's biology drives everything: the bacteria favour 20–45 °C and survive between 6 and 60 °C. The regime keeps water out of the danger band:

One metric the document implies but no lab report shows: how many hours per day your water spends inside the 20–45 °C growth band. A quarterly culture is a snapshot; the hours-in-band figure is the film. It is also the single number that predicts what the next culture will say.

3. Laboratory limits and the action ladders

Cultures are quarterly for all systems (monthly aerobic counts for cooling water), to ISO 11731, sampled per BS 7592, by EIAC-accredited laboratories. The limits: legionella below 1,000 cfu/l for cooling and domestic hot/warm/cold systems; for fountains, water features, spas and jacuzzis the stricter figure of less than 1 cfu/l ("not detected") applies. A caution when reading lab reports: the document quotes legionella in cfu per litre and aerobic counts in cfu per millilitre — a thousandfold difference that has confused more than one facilities report.

Exceedances do not trigger a fine; they trigger a prescribed sequence of actions:

For cooling towers the critical rung goes further: turn the tower off, clean and disinfect immediately, and restart only when legionella is under 100 cfu/l and aerobic counts under 10,000 cfu/ml. For a hotel or a data-centre-adjacent facility in August, an offline cooling tower is not a compliance footnote — it is an operations incident.

4. The reporting burden — the real cost centre

This is where GU44 differs from every other guideline on this site. The recurring workload it creates:

• Daily records of disinfectant levels and hot/cold water temperatures at a minimum of four different locations or floors per day (Schedule 1), plus daily cooling-water records where towers exist (Schedule 2).
• Record forms submitted every two weeks to [email protected], signed by the person in charge.
• Weekly updates through DM's Building Health and Safety self-Compliance Test Reports e-services portal. (The document states both channels; confirm with DM which governs your facility.)
• A twelve-task maintenance calendar — from daily sand-filter backwash, through quarterly shower-head disinfection, to six-monthly system flushes and tank cleaning — each with dates and results retained.
• Eight categories of standing documentation (§12.3): risk assessment, sampling-point layouts, schematics, system volumes, treatment procedures, responsible personnel, and all test results — available whenever a DM inspector asks.

Price that in man-hours: a daily walk to four or more points with a probe and a clipboard, a fortnightly collation and submission, and a calendar that never stops. That — not the sensor — is what a facility actually pays for legionella compliance today.

5. What the WOLKIS platform actually is

Asked plainly: WOLKIS is a water safety monitoring platform — sensors on the pipes, a dashboard in the browser, and a digital logbook that fills itself. Building managers who go looking for “a Legionella app” or “water safety software” are usually looking for four things, so here they are without the marketing:

• Continuous records instead of a logbook. Hot and cold pipe temperatures are logged automatically, every reading timestamped. Nothing is typed in by hand, so nothing can be back-filled the evening before an audit.
• A dashboard that shows time-in-risk-band. Not raw numbers — how many hours each loop spent between 20 and 45 °C, which is the question a risk assessment actually asks.
• Alerts that name the location. An excursion sends the duration and the point, not a generic warning, so the engineering team knows where to go.
• Reports in the authority's format. The record is exported as the document an inspector expects, rather than as a spreadsheet someone has to reformat.

What the WOLKIS platform is not: it is not a laboratory, and it does not detect Legionella pneumophila. No sensor does. It monitors the conditions under which the organism proliferates and it documents them continuously — laboratory sampling remains a separate obligation and a separate invoice.

6. What we automate, and what we honestly do not

Our Legionella Watch module places temperature sensors on the vessels and lines where the regime is won or lost — storage, flow and return, cold-water risers — and does four things:

• Continuous temperature control against the GU44 regime, with alerts the hour a calorifier drifts below 50 °C or a cold line climbs past 20 °C — instead of discovering it in the next quarterly culture.
• The hours-in-growth-zone metric (20–45 °C) per system — the early-warning number no quarterly snapshot provides.
• Automatic assembly of the biweekly DM pack in the guideline's own record format, ready for [email protected] on schedule, with the twelve-task maintenance calendar tracked alongside.
• A tamper-evident log — readings and reports that cannot be rewritten after the fact, which matters the day an incident investigation starts.

And the boundaries, stated plainly: sensors do not detect legionella — only ISO 11731 culture by an EIAC-accredited laboratory does, quarterly, and we do not draw the samples. The outlet-temperature check ("50 °C after one minute of running") is a flow-conditional measurement a static sensor cannot honestly claim. The risk assessment GU44 requires is a competent person's work, not software. We automate the regime, the records and the submission — the three things that consume staff time every single day.