A failing concrete water tank is two problems at once: water loss and water quality. Cracks and failed joints let water out (and, for underground tanks, groundwater in), while a peeling old coating and exposed concrete can affect what comes out of your taps.
Signs your tank is failing
- The wall or ground next to an underground tank is always damp
- The level drops overnight with no water being used
- Rusty, discoloured or smelly water, or sediment in the tank
- Old coating peeling off in sheets
- Cracks or rust staining visible on the inside walls
Why tanks fail
Concrete tanks are under constant water pressure and, in the UAE, exposed to high temperatures on rooftops or salty groundwater below ground. Over time, shrinkage cracks open, pipe sleeves pull away from the concrete, and older bituminous or paint-type coatings break down. Once water reaches the reinforcement, rust expands and cracks the concrete further.
How a tank is properly waterproofed
- Drain and clean. The tank is emptied, sludge removed and surfaces washed.
- Remove failed coatings back to sound concrete — anything loose is both a leak path and a contamination risk.
- Repair the concrete. Cracks filled or injected, exposed rebar treated, and pipe entries and the manhole frame sealed.
- Apply a food-grade lining — a potable-certified epoxy or cementitious system on the walls, floor and soffit.
- Cure, flush and refill. The lining cures fully, the tank is flushed and cleaned, then refilled.
Is the lining safe?
It has to be. We only use linings certified for drinking-water contact, applied at the specified thickness and cured for the full time the manufacturer requires before the tank is flushed and put back in service.
How long will you be without water?
For most villa tanks, two to four days. For buildings, the work can be planned around a temporary supply, or done one compartment at a time where the tank is split.
Underground tanks and groundwater
In coastal and low-lying parts of Dubai and Sharjah, underground tanks can also take in groundwater through cracks. Lining from the inside, with crystalline treatment and injection where needed, protects against that pressure — see basement waterproofing for the same principle below ground.
Ready to fix it? See our water tank waterproofing service.