Water Tank Cleaning in Dubai: Municipality Rules

In Dubai, Dubai Municipality's technical guidelines require building water tanks to be emptied, cleaned and disinfected with 50 mg/L of chlorine at least twice a year, kept covered and inspected internally at least monthly, and cleaned only by a company approved by Dubai Municipality's Food Safety Department, Registration and Permit Section. Water samples are tested by an EIAC-accredited laboratory a week after each cleaning and at least every six months, and cleaning reports and test results are kept for inspectors. Power Zone cleans and disinfects tanks across Dubai with its own teams.

Updated 17 October 2026. Every rule in this guide links to its official source at the end of the page.

Key facts

Frequency: all water tanks emptied, cleaned and disinfected with 50 mg/L of chlorine at least twice a year, under Dubai Municipality's drinking water and Legionella guidelines.
Monthly check: tank covers intact and fixed in place, and tanks inspected internally at least monthly.
Who cleans: the cleaning company must be approved by Dubai Municipality's Food Safety Department, Registration and Permit Section.
Testing: samples collected a week after each regular cleaning and at least every six months, by a laboratory accredited by the Emirates International Accreditation Center (EIAC), against UAE.S GSO 149:2021.
Chlorine in supply: residual free chlorine in unbottled drinking water of 0.2 to 0.5 ppm.
Records: cleaning, disinfection and laboratory reports kept and shown to the Health and Safety Department inspector on request; inspection, cleaning and sampling reports kept for five years where there is no electronic system.

The two Dubai Municipality guidelines that govern tanks

Most Dubai buildings store their drinking water in tanks, on the roof, at ground level or below ground, before it reaches taps and showers. Dubai Municipality's Health and Safety Department, through its Environmental Health Section, sets the rules for keeping that water safe in two technical guidelines that work together:

Code	Title	Version	What it covers
DM-HSD-GU17-DW2	Technical Guidelines for Quality of Unbottled Drinking Water	Version 1, issued 25 September 2024	Roles of the municipality, building owners, cleaning companies and laboratories; water safety plans; tank, cooler, filter and ice machine requirements; testing and records
DM-HSD-GU44-LCWS2	Technical Guidelines for Legionella Control in Water System	Version 6, issued 19 August 2025	Legionella controls, including tank cleaning and disinfection frequency, a step-by-step tank disinfection method, temperatures and records

The drinking water guideline applies to the buildings and facilities in its scope, and also to companies, tankers and suppliers of unbottled drinking water, ice manufacturing systems in those buildings, companies that clean and disinfect water systems, and private laboratories that test water. It requires unbottled drinking water to meet all the conditions of the mandatory UAE standard UAE.S GSO 149:2021, and refers to Council of Ministers Decision No. 26 of 2013 concerning the UAE system for drinking water control.

This page explains the tank-related parts of both guidelines in the order a building owner or facility manager needs them. Related Dubai guides: plumbing in Dubai, commercial building maintenance and the Dubai property maintenance schedule.

Who is responsible for what

The drinking water guideline divides responsibility between four parties:

Party	Responsibilities under DM-HSD-GU17-DW2
Dubai Municipality	Controls and inspects buildings in scope; issues circulars and notifications; may collect samples from any water supply point; takes legal measures against violators
Building owner or representative	Applies the guideline in the building; carries out corrective actions, including cleaning and sterilising tanks and maintaining tanks and pipes; develops a water safety plan; contracts an EIAC-accredited laboratory; keeps records; notifies the authorities of non-compliant results
Tank cleaning and disinfection company	Must be approved by Dubai Municipality's Food Safety Department, Registration and Permit Section; follows the approved cleaning and disinfection methods; prepares and keeps reports; trains and assesses workers; keeps workers safe, including confined space training certificates; reports tank or water problems to the owner
Private laboratory	Must be EIAC-accredited; tests samples to GSO and EIAC standards; informs the Health and Safety Department of non-conforming samples

For owners, the key point is that the duty stays with the building even when work is outsourced: a contract with an approved company and an accredited laboratory is how the owner meets the duty, and the paperwork they produce is the owner's evidence.

How often tanks must be cleaned and checked

The two guidelines set the same core frequencies for tanks. The drinking water guideline lists them among the regular maintenance procedures building owners must follow, and the Legionella guideline repeats them for the premises it covers:

Item	What the guidelines require
Water tanks	Emptied, cleaned and disinfected with 50 mg/L of chlorine at least twice a year
Tank covers and condition	Tanks protected from contaminants, covers intact and fixed in place, and tanks inspected internally at least monthly
Tank and fittings	Checked and maintained periodically
Visual inspections	Regular visual inspections at least every week to avoid build-up of dirt, organic matter or other substances in tanks and water flowing from points of use
Hot and cold water system	Disinfected with chlorine to give a free residual of 1 to 2 mg/L for 1 hour, with each outlet run for at least 5 minutes, at least twice a year and if bacteria are detected
Water heaters (calorifiers)	Kept clean, drained and disinfected at least twice a year
Unoccupied rooms	Taps and showers run for several minutes at least once a week, and always before occupation

These are minimums. Both guidelines also call for cleaning and disinfection whenever inspection or testing shows a problem, as explained below.

How a tank is cleaned and disinfected, step by step

Section 21-1 of the Legionella guideline gives a step-by-step method for cleaning and disinfecting water tanks with chlorine:

Empty the tank: completely drain all water before starting.
Initial cleaning: clean the internal walls and floor with a soft brush and clean water, using approved cleaning products if there are stubborn deposits.
Rinsing: rinse thoroughly with clean water several times to remove all chemicals and sediments.
Prepare the chlorine solution: at a concentration of 50 parts per million, using chlorine-based disinfectants according to the packaging instructions.
Fill the tank: fill with clean water to three quarters of its capacity, add the chlorine solution and stir to distribute it evenly.
Disinfection: leave the water and chlorine solution in the tank for at least 4 to 6 hours; the guideline states that the chlorine concentration should be maintained between 1 and 2 ppm during this period.
Final rinsing: rinse again thoroughly with clean water to remove all chlorine residues.
Refill: refill completely with clean water and check there are no leaks or malfunctions.
Quality verification: collect a water sample and send it to an accredited laboratory, at least 48 hours after refilling, to confirm there is no remaining contamination.

The same guideline adds practical safety rules for chlorine disinfection: chlorine's effectiveness depends on pH, and pH values above 7.6 should be avoided; warning signs and labels indicating that disinfection is in progress must be installed in all water-use areas; and pre-disinfection should be carried out if conditions inside a tank are so poor that they could affect the comfort and health of the cleaning personnel.

When the whole water system must be disinfected

Tank cleaning is one part of keeping water safe; the pipes, heaters and outlets matter too. The Legionella guideline lists the situations in which water system disinfection should be performed:

on completion of a new water system, or after renovation of hot and cold water systems;
when new components are installed, especially those pressure-tested with water by the manufacturer;
if the hot and cold system has not been used for an extended period, has not been drained as recommended, or control measures have been ineffective for a long time;
if there is evidence of contamination or significant sediment during periodic inspection of water storage tanks;
if the system or part of it has been substantially modified or opened for maintenance in a way that may cause contamination;
after sampling results show microbial contamination;
during or after an outbreak or suspected outbreak of Legionnaires' disease.

For the internal distribution network, section 21-2 of the guideline describes shutting the building's main water valve, opening drainage taps to drain the system, preparing a chlorine solution of 1 to 2 ppm and distributing it through all pipes and fixtures. In practice, this means tank cleaning, network disinfection and flushing are best planned together, so clean tank water does not refill dirty pipes.

Testing: when, where and by whom

The drinking water guideline requires the building owner to contract a laboratory accredited by the Emirates International Accreditation Center (EIAC) to collect and test water samples, with drinking water samples taken once every six months for laboratory tests against the parametric values in UAE.S GSO 149:2021. Its section on sampling lists when samples must be collected:

Trigger	When samples are collected
After regular cleaning	A week after the regular cleaning and disinfection (every six months)
After emergencies	A week after sterilisation and disinfection for emergencies, or after reports or notifications of illness from water use in the building
After contamination findings	After disinfection following pollutants found in Dubai Central Laboratory or private laboratory reports
Periodic	At least once every six months
After changes	After any major changes, additions or maintenance to the building's water system
New sources	When a temporary or permanent water source is added to the building

Samples are taken from taps after correct sampling procedures; from the water tank, through a faucet prepared for sampling at the outlet or, if taken from the tank itself, from under the water surface; from water coolers; and from ice machines. Sampling must follow ISO 19458:2006 on sampling for microbiological analysis, and samples must reflect the building's water system, be protected from contamination, stored so they do not change, and analysed as soon as possible. The guideline also states that unbottled drinking water must be completely free from disease-causing microbes, coliform microbes and viruses, and free from algae, fungi, insects and their larvae, and protozoa.

Chlorine, temperature and the conditions bacteria like

Both guidelines set operating targets that help keep water safe between cleans:

Parameter	Target in the guidelines
Residual free chlorine in unbottled drinking water	0.2 to 0.5 ppm
Hot water storage	At a minimum of 60°C, with 50 to 60°C maintained and circulating throughout the hot water system
Hot water at outlets	Recommended to reach at least 50°C at points of use after one minute of operation
Cold water	Stored and distributed at or below 20°C, at all outlets
Small water heaters (up to 15 litres)	Water kept close to 60°C
Calorifier settings	Flow temperature set as close to 60°C as possible but not below 60°C; return temperature not less than 50°C

The drinking water guideline also lists the conditions that encourage microbial growth in building water systems, which read like a maintenance checklist: stagnation and low flow; poor temperature control, for example uninsulated hot and cold pipes; scale and corrosion that create rough surfaces for biofilm; suspended matter and settled sludge; poor design with long branch pipes and dead ends; poorly maintained or intermittently used equipment such as ice machines and old carbon filters; oversized tanks that cause stagnation and temperature stratification; and temperature-reducing devices placed too far from outlets. It also requires dead legs, pipe ends and stagnant pipes to be removed or avoided from the building entry to the points of use.

The Legionella guideline adds, for the premises it covers, a supplementary automatic chlorine dosing system at the tank connected directly to the main supply to keep 0.2 to 0.5 mg/L at the terminal points, and daily records of water treatment readings such as temperature, pH, chlorine and biocide concentrations. Power Zone provides pipe insulation, water heater maintenance and water filtration.

The building's water safety plan

The drinking water guideline requires the building owner or representative to develop a plan for the safety of the building's water systems, including:

diagrams of the water systems, updated at intervals or after significant changes;
identification of hazards: microbiological (bacteria, viruses, protozoa), chemical (from outside sources, processes, unsuitable materials or corroding pipes such as copper, lead, cadmium and nickel) and aesthetic (odour, taste, colour);
a safety plan suited to the building's users, whether residents or visitors, elderly or young, such as schools, hotels and nurseries;
a team of employees responsible for water system safety, trained to control physical, chemical and microbiological hazards;
monitoring procedures for all identified risks;
corrective and preventive measures, covering emergency action and documented corrective actions;
audit, testing and administrative control, with an administrative review annually and after each severe deficiency in the water system.

The guideline also calls for a person responsible for water safety and quality in the building, trained on water safety and quality, and for appropriate training of maintenance personnel. For most buildings, the practical approach is a short written plan, a single responsible person, and contracts with an approved cleaning company and an accredited laboratory that feed results back into the plan.

Records building owners must keep

The drinking water guideline lists the building records expected:

Record	What the guideline lists
Risk assessment	A formal risk assessment and control system for safe operation, maintenance and monitoring
Sampling plan	Locations of sampling points, based on the risk assessment survey
Drawings and manuals	All water system diagrams and operation and maintenance manuals
Cleaning and disinfection	Water tank cleaning reports and periodic water system disinfection reports
Contracts	Contracts for cleaning and disinfecting water tanks and systems
Inspections	Inspections, maintenance and the result of each inspection
Treatment	Details of treatment procedures, biocide type and method of use, and material safety data sheets for chemicals
People	Names of personnel responsible for operating and shutting down the system
Results	System tests and microbiological test results of water samples
Retention	Reports from inspection, cleaning and sterilisation companies and tank sample results kept for five years where there is no electronic system

The guideline adds that operational monitoring data must be kept for at least two years, although the municipality can set a longer period in some circumstances, and that records of cleaning, inspections and laboratory results are submitted to the Health and Safety Department inspector on request. The Legionella guideline adds that the water tank cleaning and disinfection certificate shall be valid.

What the cleaning company must do

The drinking water guideline sets clear duties for companies that clean water tanks and disinfect water systems. Owners can use them as a hiring checklist:

Area	Requirement	What to ask
Approval	The company must be approved by Dubai Municipality's Food Safety Department, Registration and Permit Section	Ask for evidence of the approval
Method	Must follow the cleaning and disinfection methods and requirements approved by Dubai Municipality	Ask for the method statement
Reports	Must prepare and keep cleaning and disinfection reports covering chemicals used, methods of use and the cleaning and disinfection mechanism, submitted on request	Ask for a sample report
Training	Must keep training records of cleaning workers and assess their efficiency	Ask how crews are trained
Safety	Must ensure worker safety, including training certificates for working in confined spaces	Ask for confined space certificates
Reporting problems	Must officially inform the building owner or the company responsible for the tank of any tank or water safety problem, leakage, overflow or weak flow, and follow up corrective actions	Expect written findings after each visit

The guideline's records section adds that the cleaning company documents and submits all inspection and cleaning reports to the control authority on request, and that the laboratory submits results of samples taken after cleaning to the regulatory authority on request and to the building owner. A company that cannot show approval, a method, sample reports and trained, certified crews is not one an owner should hand the building's drinking water to.

Water coolers, filters and ice machines

Water coolers, filters and ice machines sit downstream of the tank and can undo good tank hygiene. The drinking water guideline sets requirements for each:

Equipment	Requirements in DM-HSD-GU17-DW2
Drinking water filters	Meet UAE.S GSO 2071 with a certificate of conformity or recognised mark; maintained and cleaned as the manufacturer recommends; spare parts available so water is not used untreated
Water coolers	Meet UAE.S GSO 1811; not installed inside public toilets; cleaned periodically with municipality-approved materials; tanks closed against pollutants and insects; filters changed as the manufacturer specifies, with labels; anti-flow valve at the connection; drained, cleaned and disinfected after each long downtime of a week; cleaned and disinfected once every six months along with the building's water systems; taken out of service if contamination is suspected
Ice machines	Checked monthly, drained, cleaned and refilled per the manufacturer; sterilised every six months; removable components, water lines, air and water filters, vents and condenser disassembled and cleaned quarterly; ice tested microbiologically every six months; disconnected from the water supply before system cleaning and disinfection

For offices, schools and hotels, a tank cleaning visit is the natural moment to clean coolers and service filters too, so the whole chain from tank to glass is done on one date and recorded together.

Tank design rules in the Dubai Building Code

The drinking water guideline requires compliance with the Dubai Building Code, version 2021, Part H.5 on water supplies, and lists the relevant sections: wastewater reuse (H.5.2.7), water tank location (H.5.5.2), water storage tank sizing (H.5.5.3), water tank construction (H.5.5.4), combined firefighting and water storage (H.5.5.7), treatment against microbiological growth (H.5.6.1), water softening (H.5.6.2), servicing and isolation valves (H.5.7), backflow protection (H.5.8), controls and monitoring (H.5.9), hot water services (H.5.10), installation requirements (H.5.11) and provisions for future connections (H.5.12).

It also notes that DEWA, as the water provider, calculates tank capacity for each building based on criteria including the number of residents and daily consumption, and that storage capacity should be sufficient to supply water for at least 24 hours. Its preventive measures call for the right materials during construction, installation and maintenance, reducing water stagnation, avoiding contact between different metals to prevent galvanic corrosion, and preventing bacterial regrowth and biofilm. In practice, an oversized or poorly placed tank is harder to keep clean and cool, which is why tank replacement or modification is a design matter, not only a cleaning one.

Villas, towers, hotels, schools and offices

The guidelines apply to the buildings within their scope; the table below is guidance on how the same rules play out in different Dubai properties.

Property	How the rules apply in practice (guidance)
Villas	Roof or ground tank cleaned and disinfected at least twice a year; monthly cover and condition check; water heaters drained and disinfected twice a year; taps run after travel
Residential towers	Large tanks with water safety plan, responsible person, accredited sampling, monthly inspections, weekly visual checks, records ready for inspectors
Hotels and serviced apartments	Weekly flushing of unoccupied rooms and before occupation; hot and cold temperature control; coolers and ice machines on their own schedules
Schools and nurseries	Water safety plan suited to young users; coolers cleaned with the six-monthly cycle; extra care after holiday closures
Offices	Tank cleaning coordinated with cooler, filter and pantry equipment servicing; flushing after long closures

For multi-tenant buildings, the building owner or management handles tanks and central systems, while tenants should report taste, smell, colour, low flow or leaks promptly. See also villa maintenance in Dubai and annual maintenance contracts.

Water treatment equipment in buildings

Some buildings add treatment equipment between the tank and the taps. The drinking water guideline says treatment units are installed according to the type of water system and the purpose of treatment, and describes the main options and their limits:

Method	What the guideline says
Temperature control	Hot water stored at 60°C and distributed to reach at least 50°C at outlets within one minute; cold water at or below 20°C
Copper-silver ionisation	Can be effective against planktonic Legionella in hot and cold systems if properly managed, where copper is maintained at 0.3 to 0.8 mg/L and silver at 0.03 to 0.08 mg/L at the outlets
Chlorination	Domestic drinking water usually kept between 0.2 and 0.5 ppm at the point of delivery when used continuously; high levels can cause corrosion with prolonged use
Chlorine dioxide	Should not exceed 0.5 mg/L in drinking water; 0.1 to 0.5 mg/L can, if properly managed, be effective against planktonic Legionella; by-products chlorite and chlorate must be watched
UV and ozone	Effective downstream to the point of use and more effective at or near it, provided the systems are approved by the competent authorities
Softeners, deionisers, activated carbon, filtration	Used to control chemical pollutants; equipment chosen according to the water entering the building, through specialised water treatment companies approved by the competent authorities

Equipment that is not maintained becomes a contamination source itself: the guideline names old carbon filters past their use-by date among the conditions that support microbial growth. Treatment equipment should therefore appear in the same maintenance schedule and records as the tanks.

Water delivered by tanker

Buildings that receive drinking water by tanker, for example during works or outages, depend on the tanker operator as well. The drinking water guideline requires tankers carrying unbottled drinking water to meet UAE.S GSO 2025-2010, to be licensed by the competent authority, with qualified drivers and the necessary permits kept in the vehicle. Tankers must be filled only at approved filling stations, carry clear drinking water signs in Arabic and English, and avoid contamination during filling, transport and unloading. Dubai Municipality must be notified of any water pollution or non-conforming samples. As guidance, a building receiving tanker water should check the operator's permits, keep delivery records and include the receiving tank in its next cleaning and sampling round.

When results fail: corrective action

The drinking water guideline's section on corrective actions and non-conforming samples sets out what must happen when contamination is found:

notify the municipality and the concerned department;
prevent consumption of contaminated water until treatment is in place;
notify residents and water users of the procedures that will be applied;
provide alternative safe water until the water is treated;
disinfect the entire water system, monitoring disinfectant concentrations at points of use and verifying the result by microbiological analysis, and warn users about disinfectants that may irritate eyes or skin or cause odours;
drain the building's water and clean the entire system, including tanks and network accessories;
eliminate any source of chemical contamination, verified by chemical analysis, with a plan to treat or replace problem pipes such as lead pipes;
where heat disinfection is used, apply temperatures over 60°C, preferably over 70°C, and notify consumers to avoid burns.

The guideline also sets fines for violations, including AED 1,000 for violating health conditions related to cleaning drinking water tanks, AED 1,000 for violations by establishments and companies working in drinking water tank cleaning, and AED 20,000 for practising an activity covered by the local order without an approved permit or not meeting health requirements undertaken. Parties are first alerted to correct their situation within a set time; those that do not are fined and face legal measures.

A year-round tank and water calendar

Bringing the guidelines together, a building's water calendar typically looks like this:

When	What
Daily (where a water safety plan requires it)	Monitor residual chlorine, pH, temperature and flow at points of use; record treatment readings
Weekly	Visual checks of tanks and outlets; run taps and showers in unoccupied rooms
Monthly	Internal tank inspection; covers intact and fixed; ice machines checked, drained, cleaned and refilled
Quarterly	Ice machine components disassembled and cleaned
Twice a year	Tanks emptied, cleaned and disinfected with 50 mg/L chlorine; hot and cold system disinfected; calorifiers drained and disinfected; coolers cleaned and disinfected; ice machines sterilised
A week after each cleaning, and every six months	Accredited laboratory sampling and testing
Yearly	Administrative review of the water safety plan, and after any severe deficiency

How Power Zone cleans tanks in Dubai

Power Zone cleans and disinfects water tanks across Dubai with its own teams, part of 20 in-house teams covering all seven emirates. A typical job includes a survey of every tank, its access and condition; a written method and safety plan for confined space work; notices for residents; draining, cleaning, chlorine disinfection, rinsing and refilling following Dubai Municipality's method; and a report covering the chemicals used, the method and findings. Where testing is required, sampling is arranged with an EIAC-accredited laboratory. Related services include water tank cleaning, pump maintenance and leak detection. See how every job runs or request a site survey.

Frequently asked questions

How often must water tanks be cleaned in Dubai?

Dubai Municipality's guidelines require all water tanks to be emptied, cleaned and disinfected with 50 mg/L of chlorine at least twice a year, and inspected internally at least monthly.

Who can clean water tanks in Dubai?

A company approved by Dubai Municipality's Food Safety Department, Registration and Permit Section, following the cleaning and disinfection methods approved by Dubai Municipality.

How is a tank disinfected under Dubai Municipality's method?

Drain completely, brush clean, rinse, prepare a 50 ppm chlorine solution, fill to three quarters and mix, leave for at least 4 to 6 hours, rinse, refill and send a sample to an accredited laboratory at least 48 hours after refilling.

When must water be tested after tank cleaning?

Samples are collected a week after the regular cleaning and disinfection, and periodic samples at least once every six months, by an EIAC-accredited laboratory against UAE.S GSO 149:2021.

What chlorine level should Dubai drinking water have?

The drinking water guideline sets residual free chlorine in unbottled drinking water at 0.2 to 0.5 ppm.

What temperatures should hot and cold water be kept at?

Hot water stored at a minimum of 60°C with 50 to 60°C circulating, and cold water at or below 20°C at all outlets.

Do unoccupied rooms need flushing?

Yes. Taps and showers in unoccupied rooms should be run for several minutes at least once a week, and always before occupation.

What records must a Dubai building keep for its water system?

Risk assessment, sampling plan, drawings and manuals, tank cleaning and disinfection reports, contracts, inspection results, treatment details with safety data sheets, responsible personnel and test results.

How long are tank cleaning records kept?

Reports from inspection, cleaning and sterilisation companies and tank sample results are kept for five years where there is no electronic system; operational monitoring data for at least two years.

What happens if a water sample fails?

Notify the municipality, stop consumption, inform residents, provide alternative safe water, disinfect and clean the whole system, remove any chemical contamination source and verify by analysis.

What is the fine for violating tank cleaning conditions in Dubai?

The guideline lists AED 1,000 for violating health conditions related to cleaning drinking water tanks, and AED 1,000 for violations by companies working in tank cleaning.

How often should water coolers be cleaned?

Periodically per the manufacturer, after any downtime of a week, and cleaned and disinfected once every six months along with the building's water systems.

How often should ice machines be cleaned?

Checked, drained, cleaned and refilled monthly; components cleaned quarterly; sterilised every six months, with ice tested microbiologically every six months.

When must the whole water system be disinfected?

After new installations or renovations, new components, long periods out of use, contamination found in tanks, major modifications, failed microbial results, or an outbreak of Legionnaires' disease.

Are water filters and UV systems allowed in Dubai buildings?

Yes, when chosen according to the incoming water and approved by the competent authorities; UV and ozone are most effective at or near the point of use, and filters must be maintained as the manufacturer recommends.

What rules apply to drinking water tankers in Dubai?

Tankers must meet UAE.S GSO 2025-2010, be licensed, use approved filling stations, carry drinking water signs in Arabic and English, keep permits in the vehicle and avoid contamination during filling and unloading.

Should hot water heaters be turned down to save electricity?

The drinking water guideline lists reducing storage temperatures to save heating costs among the conditions that support microbial growth; storage should stay at a minimum of 60°C, with mixing devices near outlets where scald risk must be reduced.

Does Power Zone clean water tanks in Dubai?

Yes. Power Zone's own teams clean and disinfect tanks across Dubai following Dubai Municipality's method, with reports and sampling through an EIAC-accredited laboratory where required.

Water tank cleaning in Dubai: what Dubai Municipality requires, step by step