Water Tank Cleaning – Dubai Municipality Compliance (Legionella & Microbiological Control) and pipeline disinfection

From (01/01/2027 to 31/12/2029)

1. Pre-Cleaning Preparation

• Review and comply with Dubai Municipality (DM) guidelines for water storage and Legionella prevention.
• Notify building occupants of scheduled cleaning and temporary water supply interruptions.
• Obtain necessary permits and approvals if required.
• Conduct risk assessment of tank access, confined space entry, and potential hazards.
• Ensure all personnel are trained in confined space entry, PPE, and Legionella safety protocols.
• Isolate the water tank from the distribution system:
  • Close incoming mains and outlets.
  • Ensure backup water supply for essential use.

2. Equipment & Safety Measures

• Provide and wear appropriate PPE: gloves, goggles, respirators, and protective clothing.
• Use non-sparking tools for metal tanks and approved disinfectants only.
• Ensure safety signage and barriers around work area.
• Prepare equipment: brushes, high-pressure washers, suction pumps, chemical dosing pumps, and sampling kits.

3. Water Tank Draining

• Drain the entire tank completely.
• Safely dispose of or recycle residual water according to environmental regulations.
• Document water volumes and quality before cleaning (if required by DM).

4. Mechanical Cleaning

• Remove all sediment, sludge, biofilm, and debris from the tank interior.
• Scrub tank walls, floor, baffles, and roof using approved brushes and high-pressure washing.
• Pay special attention to corners, inlets, outlets, overflow points, and fittings where biofilm may accumulate.
• Remove and clean tank ladders, screens, and access covers.

5. Chemical Disinfection

• Apply DM-approved disinfectant (typically chlorine-based) at the recommended dosage for Legionella and microbiological control.
• Ensure disinfectant reaches all surfaces including dead legs, pipes, inlets, and outlets.
• Maintain contact time as per DM or manufacturer guidelines (usually ≥30 minutes).
• Flush and rinse the tank thoroughly to remove residual disinfectant.

6. Microbiological Testing

• Collect water samples before and after cleaning for microbiological testing.
  • Parameters: Legionella spp., total coliforms, E. coli, and heterotrophic plate count (HPC).
• Send samples to a DM-approved accredited laboratory.
• Ensure results meet DM potable water microbiological standards:
  • Legionella: <100 CFU/100 mL (for public facilities; check latest DM guidelines)
  • Total coliforms: 0 CFU/100 mL
  • E. coli: 0 CFU/100 mL
  • HPC: ≤500 CFU/mL (or as per DM standards)

7. Tank Refilling

• Refill the tank with DM-approved potable water.
• Flush all outlets to ensure complete distribution and removal of residual chemicals.
• Restore normal water supply to the system.

8. Documentation & Reporting

• Prepare a comprehensive cleaning report, including:
  • Pre-cleaning water quality results
  • Cleaning methodology (mechanical and chemical)
  • Disinfectant type, dosage, and contact time
  • Microbiological test results after cleaning
  • Date, time, and duration of works
  • Personnel and safety records
• Submit the report to Dubai Municipality if required and maintain a record for regulatory compliance.

9. Optional / Additional Works

• Installation or inspection of tank access covers and ladders to prevent contamination.
• Application of tank liners or protective coatings if allowed by DM.
• Installation of automatic disinfection systems or sensors for continuous monitoring.
• Periodic maintenance program:
  • Cleaning frequency: at least every 6 months or as per DM risk assessment.
  • Routine microbiological monitoring.
• Water Tank Cleaning & Disinfecting ( Yearly twice)
• 1. Domestic Tank – 225m³ | 59400 USG x 1 no. 
• 2. Fire Tank – 170m³ | 44880 USG x 1 no.
• 3. GRP Tank – 72m³ | 19008 USG x 1 no. (Partition 8+7 compartments)
• Pipeline Disinfection  Yearly Twice ,Domestic water pipeline disinfection from supply tank to entire building pipeline networks (G + 16)
• Laboratory Test TBC+Legionella test will be taken from Domestic tanks on Quarterly basis Total no. of samples 02 x 4 times (Total samples : 08 samples Yearly)