A specification for a one-piece WC is a short written document that says exactly what the factory must make, how it will be tested and how you will accept it. It should cover the standard, trap and rough-in, flush volume and system, dimensions, glaze, fittings, seat cover, packing, marking and inspection.
Attach it to every purchase order and refer to an approved sample. When something goes wrong, the specification is what you and the factory both point to.
Product and standard
- The factory's model code and your own product code, if you sell under your brand.
- The product standard your market uses, such as EN 997 for Europe or ASME A112.19.2/CSA B45.1 for North America, with the edition.
- Any certification or listing the model must hold, in whose name.
- Any water-efficiency label you need, such as WaterSense in the US or WELS in Australia.
Trap, outlet and rough-in
State the trap type (S-trap floor outlet or P-trap wall outlet) and the rough-in distance from the finished wall to the centre of the outlet. A WC that does not fit local drainage cannot be sold, however good it is. Include the outlet diameter and the connector you expect.
Flushing
- The flushing system: washdown, siphonic or rimless. Our guide on washdown, siphonic and rimless flushing explains the differences.
- The full and reduced flush volumes, for example on a dual-flush model.
- The flush performance tests the model must pass, as set by your standard or label.
- The maximum flush volume allowed in your market. Our article on flush volume rules by country gives the main limits, dated.
Dimensions and tolerances
Attach a drawing with overall length, width and height, seat height, rim shape, fixing hole positions and outlet position. Give tolerances for each dimension, or name the standard's tolerances.
Set flatness limits for the base, so the WC does not rock, and for the rim, so the seat sits evenly. State how they will be measured, such as with a straightedge and feeler gauges on a flat plate.
Body and glaze
- Body material: vitreous china, with maximum water absorption as set by the standard.
- Glaze colour, referenced to an approved physical sample, not a photo.
- Finish: gloss, matt or a named colour, and any special easy-clean coating.
- Glaze defect limits: what size and number of pinholes, spots or runs are acceptable on visible surfaces, and none inside the bowl's water area.
- Crazing resistance to the standard's test.
Fittings and seat cover
- Flush valve and fill valve type, supplier, and any certification they need.
- Flush button type, finish and position.
- Seat cover material, soft-close or standard, hinge type, and colour match to the ceramic.
- Fixing kit contents for floor and wall fixing.
- A parts list with part numbers, and a rule that no fitting changes without your written approval.
Tests and documents
List the tests you need from an accredited lab before the first order, and the routine tests the factory must run on each batch, such as flush tests and water absorption. Our guide on how sanitaryware is tested explains each test. Ask for reports that name the exact model.
Packing and marking
- Carton board grade and ply, and the type and position of foam or pulp inserts.
- One WC per carton, with fittings and seat cover packed in a named position.
- Carton markings: model, colour, quantity, gross weight, handling arrows and your barcode.
- Logo or decal position on the ceramic, if private label.
- Pallet type and treatment, if palletised.
Inspection and acceptance
Say how goods will be sampled and accepted. Many buyers use ISO 2859-1 sampling with an agreed inspection level and AQL for each class of defect. List the checks: visual, dimensions, flatness, flush test on a sample, fittings, packing and marking.
State the breakage allowance, how replacements will be shipped and the time limit for claims.
Next step
We write specifications for one-piece WCs that fit your market, get them agreed by the factory and inspect against them before loading. To start, book a free sourcing review.