An S-trap toilet sends its waste outlet straight down through the floor. A P-trap toilet sends it horizontally out through the wall. You cannot swap one for the other, and no adaptor makes a pan fit a rough-in it was not built for. Before you order anything, find out which outlet your bathroom has and measure the distance to it in millimetres.
This is the single most common reason a toilet is returned: the pan arrives, the colour is right, and it will not sit over the outlet. Checking takes five minutes with a tape.
What the two traps are
Every toilet has a trap: a bend in the ceramic that holds a small volume of water permanently, sealing the bathroom off from drain gases. The letter describes the shape of that bend and, more usefully, the direction the waste leaves the pan.
An S-trap curves down. The outlet points at the floor and connects to a drain pipe buried in the slab. This is the traditional arrangement in most Indian homes, particularly in older construction and in ground-floor bathrooms.
A P-trap curves out. The outlet points horizontally and connects to a pipe running inside or along the wall. It is the usual arrangement for wall hung pans, for bathrooms built over a waterproofed slab where nobody wanted to core through it, and in most newer apartment construction.
How to tell which one you have
If the old toilet is still in place, look at the base where it meets the floor. A pan with pipework disappearing into the floor beneath it is an S-trap. A pan with a short horizontal spigot running back into the wall, usually visible as a boxed-in section or a slight gap behind the pan, is a P-trap.
If the toilet has been removed, it is plainer still: a hole in the floor is an S-trap rough-in, a hole in the wall above floor level is a P-trap rough-in.
In new construction, ask the plumber which way the waste has been run before you buy anything. It is far easier to change on paper than in concrete.
Measuring the rough-in
"Rough-in" means the distance from the finished wall to the centre of the outlet. Two points matter in that sentence.
Finished wall means the tiled surface, not the bare brick or the skirting. If the tiles are not on yet, add the thickness of tile plus adhesive — usually 12 to 15mm, but measure your own tile rather than assuming. Skirting boards are not part of the wall; measure past them to the wall surface above.
Centre of the outlet means the middle of the pipe, not its near edge or its far edge. On a 100mm drain that is a 50mm error if you get it wrong, which is more than enough to stop a pan seating.
For an S-trap, measure horizontally from the finished wall to the centre of the floor outlet. For a P-trap, measure vertically from the finished floor to the centre of the wall outlet, and also check how far the outlet sits from any side wall, since a pan pushed tight into a corner can foul a skirting or a door frame.
Trap distances are quoted both ways and the two do not always agree neatly. The PEARL, for instance, is listed as "9 inch / 300mm" — but 9 inch converts to 229mm, not 300mm. Take your own measurement in millimetres and confirm the exact figure with us against your order before you buy. Do not order on the inch figure alone.
What the catalogue actually states
Here are the trap and rough-in figures as they appear on our own one piece and floor mount pans. Body dimensions vary widely even among pans sharing a 9 inch outlet distance: the rough-in decides whether a pan fits the drain, the width and height whether it fits the room.
| Model | Trap type | Outlet to wall | Body size | Price |
|---|---|---|---|---|
| PEARL one piece | S trap | 9 inch / 300mm | 660 x 470 x 550mm | ₹23,000 |
| CRYSTAL one piece | S trap | 9 inch | 26 x 14 x 31 inch | ₹12,000 |
| HOP one piece | S or P trap | 4 inch or 9 inch | 660 x 356 x 737mm | ₹10,300 |
| SPARCO syphonic | Not stated by maker | 9 inch | 660 x 356 x 762mm | ₹12,000 |
| JCT01001 floor mount | P trap | Wall outlet | Inbuilt flush tank | ₹23,999 |
The HOP deserves a word. It is listed at either 4 inch or 9 inch and in either trap configuration, which is why one model suits bathrooms plumbed two ways. That flexibility exists on paper — the pan you receive is built one way, so tell us which configuration you need when you order.
When each is the wrong choice
An S-trap pan is the wrong choice if your waste runs through the wall. No adaptor redirects a downward outlet into a horizontal one in the space behind a pan, and improvised extensions leak or block.
The wrong distance is equally wrong even when the drain is in the floor. A pan built for a 300mm rough-in will not seat on a drain 50mm closer. Fitters sometimes force it with an offset connector; the pan then sits proud of the wall, the fixing holes miss, and the seal stays under strain.
A P-trap pan is the wrong choice if you have a floor outlet and no scope to re-run the waste. Re-running it usually means breaking the floor screed, which on a waterproofed bathroom slab is not a small job.
Note that floor mount and P-trap are not opposites. A pan can stand on the floor and still discharge through the wall, as the JCT01001 above does. Mounting describes what carries the weight; the trap describes where the waste goes. Check both separately.
Wall hung pans and unstated trap types
Wall hung pans nearly always discharge into the wall, but several models here — the SIMON at 533mm projection, the PINTAS at 584mm, the GINOVA at 508mm and the GLISTER at 483mm — carry no manufacturer-stated trap type. We say so on each product page rather than filling the gap with a guess.
If you are buying one of these, send us your outlet position and we will confirm the configuration before the order is processed. A wall hung pan also needs a concealed frame or a load-bearing wall to carry its weight, and the flush supply is a separate purchase — browse the flushing systems alongside the pan rather than after it.
Once tiles and screed go down, the outlet is buried and you are measuring by feel. A photograph with a tape laid against the wall, taken at first fix, settles every later argument about what was actually there.
Before you order
- Identify the outlet: hole in the floor is S-trap, hole in the wall is P-trap.
- Measure from the finished wall or floor, allowing for tile and adhesive if not yet laid.
- Measure to the centre of the pipe, not its edge.
- Record the figure in millimetres and keep the photograph.
- Check the pan's body width and height against the room, not just the rough-in.
- Confirm trap type and distance with us in writing before the order is processed, especially on a model listed in more than one configuration.
- For a wall hung pan, confirm the wall can carry it and order the concealed cistern at the same time.
Measuring a rough-in is the least interesting five minutes of a bathroom project and the one that most often decides whether the rest of it goes smoothly. The same habit applies elsewhere in the room — our guide on how to choose and install a bathroom vanity covers the equivalent checks for basin and waste positions. When you have your figure, the full range of pans is in toilets, with the sensor and heated-seat models in intelligent toilets. Send us the measurement and we will tell you plainly which pans fit and which do not.