Repairing a Building Water Tank in Abu Dhabi Without Cutting the Supply

A leaking water tank in an apartment or office building is a different problem from a leaking villa tank. The building cannot switch off its water for days, and every resident notices. Abu Dhabi's water supply rules already plan for this, as long as the repair is sequenced correctly.

What do the Abu Dhabi rules say?

The Department of Energy's Water Supply Guide (2024) requires storage tanks larger than 50,000 litres to be divided into compartments, or backed by a second tank, so that cleaning and maintenance do not interrupt the supply (clause 4.9.1). The dividing wall must be designed to hold water with one side empty (clause 4.12.8).

In practice, this means most building tanks can be repaired one compartment at a time. One compartment is isolated, drained and repaired while the other keeps supplying the building. Smaller single-compartment tanks, typical of villas and small buildings, need a short planned shutdown instead, scheduled with the occupants.

What are the signs that a building tank is leaking?

• Damp patches, salt deposits or rust stains on the outside faces of the tank, or on the ceiling or walls of the room below a roof tank.
• Damp in basement rooms next to an underground tank.
• The water level dropping overnight with the outlets closed.
• Cracks, leaking pipe sleeves or exposed steel noted during tank cleaning.

Tank cleaning is the best time to find defects, because the inside is empty and visible. Ask the cleaning contractor for photographs of the walls, floor and pipe entries at every cleaning visit.

How is a partitioned tank repaired?

1. Plan the isolation. Agree with the facilities team which compartment goes first, check that the isolation valves hold, and confirm that the remaining compartment can meet demand at peak hours.
2. Drain, clean and enter safely. The compartment is drained, cleaned and ventilated. A tank is a confined space, so entry follows a permit with gas testing, ventilation and an attendant outside.
3. Internal survey. Cracks, construction joints, pipe sleeves and areas of poor concrete are mapped and photographed.
4. Repair. Cracks and joints are injected with a polyurethane resin whose data sheet states that the cured resin is suitable for contact with potable water. Where the surface has deteriorated, a potable-water-grade lining is applied.
5. Cure, test and disinfect. The repair cures for the time given on the data sheet. The compartment is then filled and watched for seepage, and cleaned and disinfected under the building's tank-cleaning procedure before it goes back into service.
6. Second compartment. The same sequence is repeated on the other side, with the repaired compartment now supplying the building.

One complication is worth checking first: if the dividing wall itself leaks, water from the full compartment seeps into the one being repaired. The dividing wall then becomes the first repair, and it may need both sides drained for a short, planned period.

Which materials are acceptable in a drinking-water tank?

Only products whose manufacturer data sheets state that they are suitable for contact with potable water once cured. Ask for those data sheets before work starts, along with any drinking-water approvals the product holds, such as WRAS in the UK or NSF/ANSI/CAN 61. Ordinary construction resins and coatings without that statement do not belong in a drinking-water tank. Our water tank waterproofing guide covers the materials and indicative costs in more detail.

What documents should the building receive?

• A method statement and risk assessment covering confined-space entry and the isolation sequence.
• Technical and safety data sheets for every product, showing potable-water suitability.
• A photographic record of each compartment before and after the repair.
• The result of the fill-and-observe check, and a completion report.

Tanks are one of the areas a planned maintenance agreement should cover, timed with the tank cleaning visits. For how we work with facility managers and building owners, see leak repair for managed buildings.