A sink that does not connect to locally available plumbing fittings is unsellable, and the problem is only discovered after the container has landed. This is one of the few specification errors that cannot be worked around at the warehouse.

This article explains the three interfaces that have to match, how to verify them against your own local supply before committing, and what to put in the enquiry. It is written for importers, distributors, cabinet manufacturers and installers buying through distribution.

The three interfaces that must match

Everything on the plumbing side comes down to three connection points:

1. The drain (waste) opening in the bowl, which the strainer or waste kit fits into and which then connects to the trap.

2. The faucet hole in the tap ledge, which the mixer body passes through.

3. The overflow connection, where the sink has one.

A fourth item is not an interface but constrains all of them: the physical space under the bowl for the trap to sit. A perfectly compatible drain is no help if the siphon fouls the cabinet.

Get these four checked and the plumbing risk on an order is essentially closed.

Drain (waste) hole diameter

The drain opening diameter determines which strainer and waste kits will fit. It is the single most consequential number on this page and the one most often assumed rather than checked.

There is no site-wide drain diameter for our range. The value is per model. It is stated on the individual product page where it has been verified, and where it is not stated it has not been verified — in which case ask us for that specific model rather than inferring it from another one.

We are deliberate about this because assuming a common diameter across a range is exactly how a container of sinks arrives that will not take the strainers already in your warehouse.

What to do:

• Take the drain diameter from the specific model page, or ask for it in the enquiry
• Check it against the strainer and waste kits you can actually source in your market
• If you are stocking multiple models, list the diameter per model rather than assuming they align
• If the sink is supplied with a strainer in the carton — verify per model, see what is and is not included — confirm that the supplied item is what you intend to sell with it

Faucet hole: diameter, position and knock-outs

The faucet hole has three attributes and all three can cause a mismatch.

Diameter. Standard mixer bodies fall in a narrow range, but the hole has to accommodate the specific body, not the category. Confirm the hole diameter for the model against the mixers you sell alongside it.

Position. Where the hole sits on the tap ledge affects the reach of the spout over the bowl and whether the mixer body clears the wall behind. A hole positioned for a double bowl sits differently from one positioned for a single bowl with a drainboard.

Presence and knock-outs. Some models arrive with the hole already punched, some with a knock-out that the installer opens, and some with no hole at all for undermount installations where the mixer is fitted to the worktop. These are different products from an installer's point of view. Confirm which applies per model, and make sure your own listing says so, because "no tap hole" arriving where a hole was expected is a return.

The faucet itself is not included with any sink in our range. If your product photography shows a mixer, state clearly in your copy that it is not supplied.

Overflow connection

Where a sink has an overflow, it introduces a second connection that has to be routed to the waste.

Points to check: whether the model has an overflow at all — many do not, and both configurations are normal; whether the overflow kit is included in the carton or has to be sourced; and whether the connection type matches the waste fittings available locally.

Markets differ in whether an overflow is expected as standard on a residential sink. Establish what your market expects before choosing which models to carry, because it is a visible feature that customers notice on the shelf.

Siphon clearance under the bowl

This is a spatial constraint rather than a dimensional interface, and it is where cabinet-mounted installations most often go wrong.

The trap has to fit between the underside of the bowl and the cabinet base, clear of the carcass and of anything stored or built under the sink. Three things drive the available space:

• Bowl depth. A deeper bowl leaves less room underneath. This is the main trade-off in compact kitchens.
• Drain position. A centred drain puts the trap in the middle of the cabinet; a rear or offset drain moves it back and frees usable space.
• What else is under there. A drawer box, a waste disposal unit or a water filter each consume part of the same volume.

Bottle traps, space-saving flat traps and standard tubular traps all need different clearances. If your market predominantly uses one type, check the models against it rather than against a generic assumption. For cabinet manufacturers this belongs in the design stage — see sink specifications for kitchen furniture manufacturers.

What changes between single and double bowl

A double bowl introduces connections that a single bowl does not have.

Two bowls normally mean two drain openings joined into one trap through a connecting piece. That connector is part of the waste assembly, it takes vertical space, and it has to be compatible with the trap. A double-bowl installation therefore needs more clearance under the sink than a single bowl of the same depth, not the same.

Bowls of unequal size may sit at different depths, which changes the routing again. And a model with a drainboard may position the drain differently from the same bowl layout without one.

The practical rule: check clearance on the actual configuration, not on the model family. Model 8050 is a good illustration — it exists in more than one confirmed configuration, and the plumbing layout is not the same across them. Always work from the specific product page for the variant you are ordering.

How to check compatibility with your local supply

The reliable method is physical, not documentary.

1. Order a sample of each model you are considering.

2. Buy the strainer, waste kit, trap and mixer that you actually sell or that are commonly available in your market.

3. Assemble them onto the sample sink, in a cabinet of the depth you will be selling into.

4. Photograph the assembly and record what fitted and what did not.

5. Keep that record as the reference for the production order.

This takes a few days and closes the largest avoidable risk in a sink order. Doing it on paper — comparing a dimension on our page with a dimension on a fitting manufacturer's page — catches most problems but not clearance issues, which only appear when the parts are physically together.

What to confirm before ordering

Send this with the enquiry and we will answer it per model:

Models under consideration:
Drain opening diameter required (or fittings you intend to use):
Faucet hole: required / knock-out / none
Overflow: required / not required
Trap type common in your market:
Cabinet depth and under-sink constraints:
Bowl configuration required (for multi-variant models, state the exact variant)

We will confirm the interface dimensions we have verified for those models, and tell you plainly which ones we have not verified rather than supplying a number that looks right.

The under-sink fitting set is included with our sinks; the faucet is not. Production lead time is 35 days, minimum order quantity is 200 pieces per model for pressed sinks, 50 pieces for handmade and 20 pieces for quartz composite, which is supplied to us by a partner factory. We quote EXW and FOB.

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