The following measures should be taken during construction of a water tank to prevent the leakage. These preventive measures do not need any additional expenditure yet they are very effective in making a water tank leak-proof.
1. Keep the water tank 2 to 3 feet high from tile tracing of the roof for easy repair and cleaning in future.
2. Keep the ratio of cement concrete 1:1.5:3 for RCC slab for the bottom the tank and it should be vibrated.
3. Finish the top of slab with water proofing compound and cement slurry while laying the slabs.
4. Plaster the bottom of the slab after removing the shuttering.
5. Fix all the water supply pipes during masonry work.
6. Plaster internal and external surfaces of the water tank with coarse sand in cement sand mortar 1:3 and rendered with cement slurry.
7. Finish all the joints properly and they should be round.
8. Fix proper overflow pipe which discharges into the rainy water pipe directly.
9. Fix ball cock with the water tank.
10. Fit all other joints of water supply pipes tightly.
NOTE: If you want to construct an insulated tank, follow the steps given below.
1. Make the bottom slab of water tank, 6 to 8 inches wide on all four sides.
2. Construct the external wall leaving the gap, 2 to 4 inches between the two walls after finishing the internal of the tank with plaster on both sides.
3. Finish the external wall with cement plaster all around.
4. Fill in the gap between the two walls with insulated materials.
5. Cover the top of water tank with insulated material.
6. Cover all the water supply pipes on the roof either with insulated material or kept in PVC pipes.