Single Hole Kitchen Faucet: Install and Sizing Guide for Buyers

Table of Contents

Single hole kitchen faucet with 35–40 mm hole size diagram, deck plate, lock nut, thread tube, washer and triangle under-deck support for buyer install review.
Figure: A single-hole kitchen faucet still needs the correct hole diameter, deck plate coverage, thread tube length and under-deck support before the order is confirmed.
Single-hole faucets make up more than 90% of the kitchen taps we ship. The reason is not the look — it is what happens the second time someone installs one.The first install goes to a pro — a three- or four-hole bridge gets set by a fitter who came to do exactly that. The second time is different. A homeowner wants a new style, or a part fails, and now someone is lying inside the cabinet trying to reach three mounting nuts in the dark. One hole means one nut. That is why our buyers order single-hole for kitchens, and why three- and four-hole runs stay small. We build these for importers and project buyers, so the production side is what we speak to here.Here is the difference a buyer is really choosing, seen at the second install.

Item Single-hole Three-/four-hole
First install pro or DIY pro fitter
Reinstall or swap one nut, doable solo three-plus nuts under the cabinet
Style change later drop-in often re-cut or re-plate
Project serviceability high low
Share of our kitchen shipments small

The numbers to lock before the order

A single-hole faucet still has to fit, and “one hole” hides the measurements that decide whether it does. Get them on the spec before tooling, not after the countertop is cut.

Measurement Typical What goes wrong if skipped
Mounting hole diameter 35–40 mm (≈ 1⅜–1½ in) hole too big, faucet won’t seat, plate won’t cover
Max deck thickness per model (shank length) thick countertop, lock nut can’t reach the threads
Hole spacing (reused holes) 3-hole outer ≈ 203 mm (8 in) deck plate too short to cover
Sink gauge and support thin sink flexes, faucet feels loose

The hole diameter runs 35 to 40 mm on our single-hole bodies (about 1⅜ to 1½ inches). “Standard” is the trap word here, because the figure that matters is the one on the model’s spec sheet, not the one a forum calls normal.

In 2022 a Gulf-region project buyer ordered a large run of kitchen faucets, single- and three-hole mixed, for a build with no retail side. We were careful, the way we are with any project: we confirmed the material, the cutout size, and the countertop’s material and thickness. Samples went out, the buyer approved them, and we reconfirmed every detail before production. Delivery went clean. Early the next year the call came with photos — the countertop had been cut to a different measurement standard, and every opening ran about 20 mm too wide. The faucets wouldn’t seat, and the deck plates couldn’t cover the gap. The cause was the cutout standard on site. We had no stock part that would close a 20 mm overshoot. We cut a one-off mold to fix that batch; at under two thousand pieces, used once, it didn’t earn tungsten tooling.

Which measurement standard a countertop shop cuts to, I can’t see from the factory — that gets set on site, after our spec leaves.

Deck thickness is the second number. The shank and lock nut only reach so far, so a thick stone countertop can leave the nut short of the threads. We give a buyer the max deck thickness per model, and the thread tube comes in 60, 70, and 80 mm to suit it.

A deck plate covers holes; it doesn’t fix spacing

Spacing only matters when a buyer reuses old holes. A three-hole sink runs about 203 mm (8 inches) across the outer pair. Our deck plate ships about 1 cm wider than the body, to cover the opening around it.

Push past the spacing the plate was built for and it stops covering. The Gulf cutouts were 20 mm out, and no standard plate reaches that. Plates come in one-hole and three-hole versions. Soap dispensers, filtered-water taps, and air switches sit outside our parts list, so a project that wants them specs them elsewhere.

Why a single-hole faucet feels loose

The last number is the sink itself. A heavy single-hole faucet on a thin stainless sink works like a lever. Pull the head down, the deck flexes, and the faucet reads as loose.

The fix sits under the deck. We fit a lock nut, a screw fixing, and a triangle support as standard, with a 201 stainless lock nut by default. A thin-gauge sink can take extra bracing, and a buyer flags that before we ship.

Reach and footprint, past the hole

The hole is one fit; the spout is another. Too little reach and the head lands behind the drain, not over it. Arc height sets the clearance under the spout, and the splash out of a shallow bowl. A wide base hides the old cutout; a narrow one can leave it proud.

The same body does not always cross to a laundry or bar sink. A kitchen single-hole built for a deep bowl can over-reach a small bar sink, or sit too tall over a shallow laundry basin. The shank length has to match the thinner deck too. A buyer moving a kitchen faucet onto another sink checks reach, height, and shank before the deck is drilled.

The same faucet, by market

The same body changes name and fitting by market. North America says faucet, deck plate, NPT; the UK, Europe, and Australia say mixer tap, and the connection runs G/BSP. We quote the hole in millimetres first, with the inch in brackets for North America.

The unit itself is the quiet risk. A faucet cut to 35 mm and one cut to 1⅜ inches are close but not identical. A countertop shop reading the wrong unit is how a cutout drifts. The Gulf overshoot started there — one side cut to a standard the spec hadn’t pinned. We write the hole in both units now, and we ask which one the countertop will be cut to.

What to pin, and what we are

We are a faucet manufacturer that reads the specs importers and project buyers send over. We build to them, we don’t sell DIY retail, and we don’t cut countertops or set a site’s measurement standard. What we put numbers on is the faucet: hole diameter, deck thickness, thread tube, and the hardware under the deck.

Our kitchen faucet range is single-hole first, with three- and four-hole on request. The under-deck hose and retraction work the same as on any pull-down kitchen faucet. A buyer mapping a project to a cutout can reach the team on the contact page.

FAQ

What size hole does a single hole kitchen faucet need?

35 to 40 mm, about 1⅜ to 1½ inches, on our bodies. Treat that as a starting point and confirm it against the model’s spec sheet, since the figure shifts by model.

Can a single hole kitchen faucet fit a three-hole sink?

Yes, with a deck plate over the outer holes. It works when the plate is wide enough for the spacing; a non-standard or extra-wide spread can leave the old holes showing.

Do I need a deck plate for a single hole faucet?

Only to cover holes you are not using. On a fresh single hole it is optional; on a three-hole conversion it is what hides the other two.

Why does my single hole kitchen faucet feel loose?

Look at the sink before the faucet. A thin stainless sink flexes when a heavy faucet levers on it, which reads as a loose faucet. Under-deck bracing — a lock nut, a screw fixing, a triangle support — is what steadies it.

What can I do with extra sink holes after fitting a single hole faucet?

Cover them with a deck plate or a hole cover, or fill them with a soap dispenser, a filtered-water tap, or an air switch. Decide before the countertop is cut, not after.

What is the difference between a single hole faucet and a single handle faucet?

Hole count versus handle count. A single-hole faucet mounts in one hole; a single-handle faucet has one lever but can still call for more than one hole. A buyer should spec both.

Can I install a single hole kitchen faucet in a laundry or bar sink?

Sometimes, but check reach and height first. A kitchen spout built for a deep bowl can over-reach a small bar sink or stand too tall over a shallow laundry basin, and the shank has to match the thinner deck.

What is the maximum countertop thickness for a single hole faucet?

It is set by the shank and lock nut, not a fixed number. We list a max deck thickness per model and offer the thread tube in 60, 70, and 80 mm, so a thick stone top still lets the nut reach the threads.

Sources

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