Water closet (W.C.) is where the maximum water is used. Generally, the parent slab of the W.C. unit has an I.W.C. Pan and concrete case of size 0.9 m x 1.2 m x 0.6 m. This case is water-proofed after fixing the necessary accessories such as P-trap, C.I. piece, W.C. pan etc. A section of the W.C. unit can indicate the various points of leakages, as listed below:

·        Joint between the C.I./P.V.C. piece and P-trap

·        Joint between the ‘tee’ of outer vertical stack and P.V.C./C.I. piece.

·        Joint between the P-trap and I.W.C. pan.

·        Joint between the flushing pipe and I.W.C. pan.

All these joints should be sealed with the proper sealant at the respective stages during the execution of the work.

For any leakages from W.C., locate the point of leakage before deciding the course of action. Breaking the tiles and water-proofing should be avoided before the leakage is traced out.

Following is the sequence of the procedure to be observed:

Mostly leakages occur through W.C., waterproofing, from plumbing pipes and fittings.

First, check the lowermost water escape pipe (drain pipe) for its operation, if it is in a working condition, leakages rarely occur as water escapes through this release pipe. If this pipe is choked, then clean it with an iron bar from outside. Also fill all the gaps in the flooring of W.C. with cement.

Check the joint between the P-trap and I.W.C. pan from above, by inserting a hand into the trap. Seal this joint with M-seal, if it is partially open.

Check the joint between the flushing pipe and I.W.C. pan by breaking only one tile, fitted exactly over the junction. Seal this joint properly with M-seal.

Open the ‘Tee’ of the vertical stack from outside, with a ladder or zula and observe the joint of C.I. piece and ‘Tee’ with torchlight and seal it properly.

If leakage still persists, break open the concealed flushing G.I. pipe and check if it is watertight. Replace the leaking pipe/G.I. fitting.

If this does not stop the leakage, break open the complete unit and check the joint at the P-trap and C.I./P.V.C. pipe. Do the new water-proofing completely with utmost care.


Generally, 90% leakages stop if we carry out the repair work as stated above, in the first four points.