An S-trap bowl drains down through the floor and a P-trap drains back through the wall, and 28 of the 52 toilet bowls live here print the set-out that has to match your pipe. Those 28 print 11 different figures, from 140mm to 300mm. Work out which way your outlet runs and measure it, then find that figure on the listing.
The short version
The trap type describes which direction the waste outlet points, based on where your existing plumbing already runs. An S-trap outlet points straight down into the floor, and it's the most common setup in older HDB flats. A P-trap outlet points out through the wall behind the bowl, and it's more common in newer builds and some renovated bathrooms.
You cannot swap a P-trap bowl onto an S-trap outlet, or the reverse, without re-routing the waste pipe. That's a plumbing job, not a toilet-installation job, so it's worth getting right at the ordering stage.
Can I convert an S-trap toilet to a P-trap, or the reverse?
Not without re-routing the waste pipe, which is plumbing work, not toilet installation. Confirm your trap type before ordering rather than after.
The Aalto ATAL8090 one-piece closet, $516.00, is listed with both configurations: S-trap at 150mm or 250mm roughing-in, and P-trap at 180mm. The two-piece ATAL8050 lists one S-trap figure, 250mm, with the same 180mm P-trap. 17 of the 28 bowls here that print a set-out give more than one figure rather than one fixed number, so match your own measurement to the listing before you order.
Eleven set-out figures are printed, from 140mm to 300mm
| Set-out | Printed against | Listings |
|---|---|---|
| 140mm | S-trap | 5 |
| 145mm | S-trap | 1 |
| 150mm | S-trap on 9; a pan type of S-trap and P-trap on 2 | 11 |
| 180mm | P-trap | 11 |
| 185mm | P-trap | 1 |
| 195mm | P-trap | 1 |
| 200mm | S-trap | 2 |
| 225mm | S-trap | 1 |
| 250mm | S-trap on 11; a pan type of S-trap and P-trap on 2 | 13 |
| 260mm | S-trap | 3 |
| 300mm | S-trap | 1 |
28 of the 52 active listings in the Toilet Bowl collection print a set-out figure, censused 19-09-2026. 52 = SANITON 25 + VERA 12 + Aalto 9 + Baron 6, reconciling against a collection count of 54 less 2 draft and 0 archived. A listing that prints two figures is counted under each, so the column sums to 50.
250mm is the most printed figure, on 13 listings, and 150mm and 180mm follow on 11 each. No other figure appears on more than five. The 24 bowls that print no set-out are 12 VERA and 12 SANITON, and seven of those SANITON listings still name P-trap in the description.
What roughing-in distance is most common in HDB flats?
It varies by flat and by renovation history, so measure your own outlet first. The Aalto ATAL8090 is listed with S-trap roughing-in at 150mm or 250mm and P-trap at 180mm. The ATAL8050 lists one S-trap figure, 250mm. A single model can carry more than one distance, so match the measurement to the specific listing.
An S-trap bowl can list two roughing-in figures
Twelve listings print two or more S-trap figures, so one model can meet a floor outlet at either distance. SANITON SERISSA ST2966, $170.00, prints three: 140, 225 and 300mm. Two Baron listings, BAW898 at $585.00 and BAW818 at $427.50, print 150mm and 250mm against a pan type of S-trap and P-trap, without saying which figure belongs to which trap. SANITON's BRASSICA ST6011 full set, $582.00, prints P-trap 180mm and adds 'Convertible to S-Trap'.
Which toilet bowls here print three roughing-in figures?
Five, as at 19 September 2026. SANITON SERISSA ST2966 prints 140, 225 and 300mm, all S-trap. SANITON VERONICA ST2977, SANITON CAMELLIA ST2488, SANITON ROSELLE ST2457 and the Aalto ATAL8090 each print two S-trap figures and one P-trap figure.
An offset pan collar, sold separately here in 1-inch and 2-inch versions at $3.43 each, can bridge a small gap between your existing outlet and the new bowl's roughing-in distance. Check the product listing first. A small mismatch is not always a dead end.
Read the trap type first, then the roughing-in
The mistake to avoid with a toilet bowl bought online is getting the trap type wrong. Get it right before you order and the new bowl fits the pipe you already have. Get it wrong and you're either returning a bowl or paying a plumber to modify your waste pipe. Here's how to check it yourself, no site visit required.
Look at your existing toilet bowl's base. If the outlet disappears straight into the floor beneath the bowl, you almost certainly have an S-trap. If there's a pipe running from the back of the bowl into the wall, that's a P-trap.
Measure the roughing-in distance. For an S-trap, that's the distance from the wall to the centre of the floor outlet. For a P-trap, it's the height from the floor to the centre of the wall outlet.
On the listing, the trap and the figure sit together in the description, but each brand labels them differently. Aalto prints 'S-trap: 250mm roughing-in'. SANITON prints 'Rough-in' or 'Available Rough-In', with the trap in brackets on some models. Baron prints a 'Pan Type' and then a 'Set Out Distance', each millimetre figure followed by an inch label.
What do the 6-inch and 10-inch labels on a toilet bowl listing mean?
They are inch labels for the set-out, and the millimetre figure next to them is the one to match. Baron's BAW888 prints '150mm(6 inch) & 250mm(10 inch)', while BAW203A prints '150mm(6 inch) & 260mm(10 inch)' and BAV800 prints '145mm(6 inch) & 260mm(10 inch)'. The same label covers 145 to 150mm and 250 to 260mm.
Not sure which trap type you have? 28 of the 52 bowls in the full Toilet Bowl collection print a roughing-in figure beside the trap type, and Plumbing Fittings & Valves carries pan collars and offset connectors.
The three most printed set-outs all start under $300
| Set-out | Listings | Lowest-priced listing | Highest-priced listing |
|---|---|---|---|
| 140mm | 5 | SANITON VERONICA ST2977, $148.00 | SANITON GARDENIA ST2234, $320.00 |
| 145mm | 1 | Baron BAV800, $326.25 | Baron BAV800, $326.25 |
| 150mm | 11 | Baron BAW203A (Urea Seat BA833), $225.00 | Baron BAW898, $585.00 |
| 180mm | 11 | Aalto ATAL8020, $291.00 | Aalto ATAL8000B, $792.00 |
| 185mm | 1 | SANITON CAMELLIA ST2488, $160.00 | SANITON CAMELLIA ST2488, $160.00 |
| 195mm | 1 | SANITON VERONICA ST2977, $148.00 | SANITON VERONICA ST2977, $148.00 |
| 200mm | 2 | SANITON LOTUS ST2322, $128.00 | SANITON VERONICA ST2977, $148.00 |
| 225mm | 1 | SANITON SERISSA ST2966, $170.00 | SANITON SERISSA ST2966, $170.00 |
| 250mm | 13 | SANITON CAMELLIA ST2488 and INDICA ST2999, $160.00 | Baron BAW898, $585.00 |
| 260mm | 3 | Baron BAW203A (Urea Seat BA833), $225.00 | Baron BAV800, $326.25 |
| 300mm | 1 | SANITON SERISSA ST2966, $170.00 | SANITON SERISSA ST2966, $170.00 |
The same 28 listings, prices read live 19-09-2026; every one is single-priced. A listing that prints two figures appears in each of its rows. Prices can change; the product page carries the current figure.
At 250mm, prices run from $160.00 for SANITON CAMELLIA ST2488 or INDICA ST2999 to $585.00 for Baron BAW898. Two listings print all three common figures, 150mm and 250mm S-trap and 180mm P-trap: SANITON ROSELLE ST2457 at $400.00, and the Aalto ATAL8090 one-piece closet at $516.00 as at 19 September 2026.
What is the cheapest toilet bowl here that prints a 250mm set-out?
SANITON CAMELLIA ST2488 and SANITON INDICA ST2999, both $160.00 as at 19 September 2026. Each prints 140mm and 250mm S-trap, and CAMELLIA adds 185mm P-trap.
Related guides
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