Water Tank Waterproofing and Leakage Repair in Pune

A leaking water tank is unusual among waterproofing problems in that it wastes something every single day, and it often damages the structure it sits on at the same time.

Where tanks leak

• Construction joints between base and walls, or between successive pours — the most common single cause
• Shrinkage cracks in the walls, usually vertical
• Failed internal coating, particularly where an unsuitable product was used
• Pipe entry points without proper sealing collars
• Honeycombed concrete from poor compaction during construction, which leaks from day one

Potable water changes the specification

If the tank holds drinking water, the internal treatment must be certified non-toxic and food-grade. This is not a detail to leave to the contractor’s discretion — ask for the product data sheet and check it explicitly states suitability for potable water contact.

Ordinary bituminous or solvent-based coatings must never be used inside a drinking water tank.

Overhead vs underground

Overhead tanks leak outward under the pressure of the water they hold, so treatment is applied internally, on the positive side. That is technically the favourable case.

Underground tanks and sumps face pressure from both directions — water inside, and groundwater outside. They usually need crystalline treatment that works within the concrete rather than a surface film, plus injection grouting for any active leak.

The process

1. Drain and clean the tank fully, removing all loose material and old coating
2. Cut open cracks and honeycombed areas, then fill with polymer-modified mortar
3. Treat construction joints and pipe entries specifically, not just as part of the general area
4. Apply the specified system in the stated number of coats with correct curing between
5. Fill and hold, checking the level over 48–72 hours
6. Flush thoroughly before returning to service

The hold test is the proof

Fill the tank and mark the level. A genuine repair holds the level over 48 to 72 hours, allowing for evaporation. Any measurable drop means the leak is still there. Insist on this before final payment.