Before you fall for a finish or a handle shape, your sink or countertop has already made the biggest faucet decision for you. The number of holes drilled in the deck, and the distance between them, decides which faucets will physically fit. This guide explains the three standard drilling patterns, shows you how to measure what you have, and covers the tricks, and the honest limits, of switching between them.
The three standard drilling patterns
Nearly every bathroom sink and vanity counter sold in Canada is drilled one of three ways, and you can filter our bathroom faucets collection by mounting style once you know which one you own.
- Single hole. One drilling that the spout and handle share, with hot and cold mixing inside the one body. The default for modern vanities and most vessel setups.
- 4-inch centerset. Three holes in a row with 4 inches between the centres of the two outer holes. Centerset faucets (sometimes written centreset) mount all three points on a single base, so the spout and both handles read as one compact unit. Very common on smaller vanities, apartment bathrooms and older homes.
- 8-inch widespread. Three independent holes with 8 inches or more between the outer centres. The spout and two handles install as separate pieces connected under the deck, which gives a roomier, more finished look and easier cleaning around each piece.
| Pattern | Holes | Outer spacing, centre to centre | Typical character |
|---|---|---|---|
| Single hole | 1 | Not applicable | Modern, minimal, easy to wipe down |
| Centerset | 3 | 4 inches | Compact, practical, space saving |
| Widespread | 3 | 8 to 16 inches | Traditional or high end, generous scale |
How to measure the holes you have
Faucet spacing is always measured centre to centre, never edge to edge. Picture three circles in a row on your sink deck. Ignore the rims of the holes. Hook your tape measure on the middle of the far left circle and read the number at the middle of the far right circle. That single measurement tells you everything.
- One hole only: you need a single-hole faucet, or a wall-mount, more on that below.
- Outer holes 4 inches apart: you have a centerset drilling.
- Outer holes 8 inches or more apart: you have a widespread drilling.
Old faucet still installed? Measure from the centre of the left handle to the centre of the right handle, since handles sit directly over the outer holes on almost every design. A quick visual check works too. If the handles nearly touch the spout base, you are almost certainly looking at 4 inches. If you could park a soap dish between a handle and the spout, expect 8.
One more word picture for anyone ordering new stone. Fabricators from Vancouver to Halifax will drill whatever you ask, but only once. A single hole centred behind the basin keeps every future option open. Three holes commit you to that pattern for the life of the counter.
Switching patterns: what a deck plate can and cannot fix
Single-hole faucet on a three-hole 4-inch sink: yes. This is the most common conversion, and the industry planned for it. Most single-hole bathroom faucets include, or offer as an option, a deck plate, also called an escutcheon, that spans roughly 6 inches and hides the two outer holes. The faucet drops into the centre hole and the plate covers the rest. Brands we carry such as Riobel, Kohler and Vogt make this nearly universal on their bathroom lines.
Centerset faucet on an 8-inch widespread sink: no. The centerset base is cast at 4-inch centres and no standard plate spans 8 inches gracefully. If your counter is drilled at 8, buy a widespread.
Widespread faucet on a 4-inch drilling: sometimes. Look for a mini-widespread. These use three separate pieces like a full widespread but are engineered for 4-inch centres. A standard widespread will not squeeze down that far, so the model name matters.
Widespread on anything from 8 to 16 inches: usually yes. Because the pieces connect with flexible supply lines under the deck, most widespread faucets tolerate a range, commonly 8 to 16 inches. Confirm the stated range rather than assuming; our guide on how to read a plumbing spec sheet before ordering shows exactly where that number hides.
Vessel sinks and wall-mount faucets
Vessel basins sit on top of the counter, so the faucet has to clear the rim. There are two answers: a tall single-hole vessel faucet drilled through the counter beside the bowl, or a wall-mount spout above it. If you are pairing a bowl from our vessel sinks collection with a deck-mounted faucet, check the spout height and reach against the rim height so water lands near the drain, not at the near edge.
Wall-mount faucets skip counter drillings entirely. The valve is roughed into the wall during the renovation and the visible trim installs at the end, which is why these faucets usually arrive in two boxes. Our guide on rough-in vs trim walks through that split. One honest cold-climate caution: think twice before running supply lines for a wall-mount faucet inside a poorly insulated exterior wall. From the Prairies to rural Quebec, a hard cold snap will find those pipes. An interior wall, or proper insulation detailing, is the safer route.
A quick note on kitchens
Kitchen sinks follow the same logic with different defaults. Most modern kitchen faucets, including pull-downs, are single hole, while stainless sinks often come punched with one to four holes. Deck plates that cover a three-hole kitchen drilling are frequently included in the box, and a spare hole can host a soap dispenser or filtered water tap.
Buying in Canada: certifications and practicalities
Whatever the pattern, look for CSA or cUPC marks on the spec sheet. Those certifications show the faucet has been tested to the standards used across Canada. The National Plumbing Code provides the framework, but provinces and municipalities adopt and amend it, so for anything beyond a simple swap in the same holes, your local code and inspector have the final word. The good news for spacing specifically: hole patterns are a fit question, not a code question, so a correct measurement is most of the battle. Everything above ships Canada-wide, whether you are renovating in Victoria, Winnipeg or St. John's.
Frequently asked questions
Can I install a single-hole faucet on a sink with three holes?
Yes, if the outer holes sit on 4-inch centres. Choose a single-hole faucet that includes or offers a deck plate and it will cover the outer holes cleanly. If the drilling is 8-inch widespread, a deck plate cannot span it, so choose a widespread faucet instead.
How do I measure faucet hole spacing without removing the old faucet?
Measure from the centre of the left handle to the centre of the right handle. Handles sit over the outer holes on nearly every faucet, so 4 inches means centerset and 8 inches or more means widespread. If there is only one visible base and no separate handles, you have a single-hole faucet.
What is a mini-widespread faucet?
A faucet with three separate pieces, spout plus two handles, engineered to fit a 4-inch three-hole drilling. It gives the widespread look on a centerset sink, which a standard widespread cannot do.
Are 8-inch widespread faucets always exactly 8 inches?
No. Most widespread faucets adjust across a range, commonly 8 to 16 inches, because the parts connect with flexible lines below the deck. Check the minimum and maximum spread on the spec sheet before ordering, especially for unusual custom drillings.
