​​​​​Contract Duration:
 The contract shall be for a fixed term of three (3) years. The quotation must be submitted on an annual-price basis, with the annual price remaining fixed throughout the contract period.

The scope of work for the annual maintenance contract includes, but is not limited to, the following activities:

• Clean and disinfect all designated water tanks two (2) times per year—once every six months—or as required by the First Party.
• Carry out the work in compliance with the requirements of the relevant government departments and Dubai Municipality.
• Collect water samples from all designated water tanks and water systems quarterly.
• Lab Tests: Microbiology and Legionella.
• Submit cleaning certificates, laboratory test results, detailed service reports, and before-and-after photographs.
   

Potable Verification Test

After a water tank is cleaned and disinfected, Dubai Municipality mandates a "Potable Verification Test" to prove the tank is free of dangerous bacteria and that no toxic chemical residue remains from the cleaning process.
 

The mandatory post-cleaning test package must be processed by an EIAC (Emirates International Accreditation Centre) accredited laboratory and includes three main categories of testing.
 

1. Chemical & Disinfection Residue Tests

These tests ensure the high-strength chlorine used to disinfect the tank walls has been thoroughly rinsed out and is safe for human consumption.

• Residual Free Chlorine: Must measure strictly between 0.2 ppm and 0.5 ppm. Higher levels indicate insufficient rinsing; lower levels mean the water lacks disinfection protection.

• pH Levels: Must fall within 6.5 to 8.5.
   

2. Microbiological Tests (Bacterial Verification)

These tests confirm that the cleaning successfully eradicated all harmful biological pathogens and biofilms.

• Total Coliforms: Must be 0 cfu / 100ml (Zero detection).

• E. coli: Must be 0 cfu / 100ml (Zero detection).

• Heterotrophic Plate Count (HPC): Measures overall bacterial activity; must meet strict municipal safety limits.

• Pseudomonas aeruginosa: Checked to ensure no stagnant water bacteria survived.
   

3. Physical & Aesthetic Tests

These parameters ensure the mechanical scrubbing did not leave suspended dirt, sediment, or clarity issues in the system.

• Turbidity: Must be less than 5 NTU (water must be perfectly clear, not cloudy).

• Total Dissolved Solids (TDS): Must be under 1,000 ppm.

• Color & Odor: Tested to verify no chemical or stagnant smells remain.
   

⚠️ Critical Timing Window

According to Dubai Municipality technical guidelines, you cannot take the sample immediately after turning the valves back on. Samples must be collected 24 to 48 hours after the tank has been refilled with DEWA water. This timeframe allows the water system to fully stabilize and highlights if any leftover biofilm is still leaching into the water.

Vendors should submit a fully detailed proposal only after conducting a site visit to ensure that the complete scope of work and access conditions are fully understood