Measuring and selecting the correct size of the tap connection and dimensions

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Connection spacing and dimensions of the faucet – how to measure and choose the right size

One of the most common mistakes when ordering a new water faucet is underestimating the dimensions. The customer chooses a nice design, the right type, a good brand – and when it comes to installation, they find out that the faucet does not fit into the existing holes in the sink, or that the supply hoses do not reach the pipes. Result: another trip to the store, installation delay, or unnecessary costs for reducers and extension hoses. This can be avoided very easily if you know what to measure and how to measure it even before you click "order".

In this article, we will go through everything you need to know about connection spacing, hole diameter, outlet height, outlet arm length, and other dimensions that determine whether the faucet really fits. You will also find practical diagrams and tables directly in the text, so you can visualize each measurement.

Why are faucet dimensions so important – a basic issue many skip

A faucet is not just a valve with a tap. It is an assembly unit that must fit into specific holes, must reach the hot and cold water pipes, must be high enough to allow you to comfortably wash your hands or fill a pot, and at the same time must not be so high that it hits the cabinet above the sink.

From practice, I know that the most problematic situation occurs during renovations. The old trap remains, the old pipes remain, sometimes even the original sink remains – and people just change the faucet. Precisely then, all the dimensions of the new faucet must exactly match what is in the wall and in the sink. If you are buying a faucet for a completely new bathroom, you have more freedom – but it still pays to think about the dimensions in advance, before the mason embeds the plumbing.

Connection spacing – what it is and why it is the most important dimension

Connection spacing (sometimes also referred to as "axis distance of connections") is the distance between the centers of the two connection outlets – hot and cold water. It is a dimension that must match the layout of the pipes in your wall or the position of the holes in the faucet body.

There are basically two standard values of spacing in Europe:

150 mm – the European standard for most sink, shower, and bathtub faucets. The vast majority of CLAGE faucets intended for the European market have exactly this dimension.
100 mm – less common, occurs more in older installations and some specific products (e.g. some sink or technical faucets).
Non-standard dimensions – sometimes values such as 120 mm, 180 mm or others appear, especially in older Czechoslovak installations or imported products from the Asian market.

If you are replacing an old faucet and you do not know what spacing you have in the wall, do not rely on the fact that it will be "definitely 150". Just measure it – a tape measure or sliding caliper, measuring from the center of one pipe to the center of the other. Five seconds of work that will save you hours of trouble.

How to measure the spacing accurately in practice

Measuring the spacing is simple, but you need to follow a few rules:

Always measure from the center of one pipe to the center of the other pipe – not from edge to edge, not from edge to center.
If you have protruding connection outlets in the wall (e.g. elbows G½"), measure from the axes of these elbows.
If you measure through plaster or tiling, be careful to get the distance between the centers of the pipes, not the surface points of the tiles.
In old installations, the spacing may be slightly eccentric – in such a case, it usually pays to connect the faucet via flexible hoses with sufficient length and slight clearance to compensate for the deviation.

Diameter and thread of the connection – G½" is the basis, but not always

Along with the distance between the connections, you also need to know the size of the thread. The vast majority of European faucets work with a G½" (external) thread on the installation side and with a corresponding internal thread on the supply side. This applies to most sink, kitchen, bathtub, and shower faucets, including CLAGE products.

Less common are G¾" threads – these are found more often in bathtub filling faucets with higher flow, or in industrial/technical faucets. If you are unsure, look at the original faucet or the technical specifications of the new product – the thread is always listed in the parameters.

Important detail: the G½" thread and the ½" NPT thread (American standard) are geometrically similar, but not interchangeable. If you have bought a faucet from the American market or from some Asian sources, be careful about this incompatibility. With CLAGE faucets, which are certified for the European market, this problem does not arise – you will always get G½" BSP.

Hole in the sink – diameter, thickness and type of mounting

Faucets are mounted either directly into a hole in the sink (upright mounting) or into the wall (wall mounting). Upright mounting is typical for most bathroom sinks.

Upright mounting – single-hole vs. three-hole

Sinks come with different numbers of holes:

Single-hole faucet – passes through one hole of diameter usually 32–35 mm. Typical for modern single-lever faucets with internal hot and cold water connections in the body of the faucet. The connections (flexible hoses) come out from under the sink.
Three-hole faucet – mounted into three holes: center for the outlet, left for hot water, right for cold water. The spacing of the outer holes is usually 150 mm (European standard). Typical for double-lever faucets and some older designs.

If you have a sink with one hole, you cannot mount a three-hole faucet without modifying the sink (which is practically impossible). Conversely – you can mount a single-hole faucet into a three-hole sink with covers that hide the adjacent holes. This solution is common in renovations, where the original ceramic sink remains.

Basin thickness and mounting thread length

This is a detail that is often not mentioned in catalogs, but in practice it causes problems. The faucet must have a sufficiently long mounting thread or body to pass through the basin and still leave space for the washer and nut to be mounted from the underside. Ceramic basins usually have an edge thickness of 15–25 mm. Modern countertop basins made of cast stone or concrete can have a thickness of up to 40–60 mm – and this is where the problem arises, because the standard mounting nut cannot reach a position where it can secure the faucet.

In such cases, there are solutions:

Extension mounting rod (thread extender) – a special part that extends the faucet thread downward so that the nut can reach under the basin.
Faucet with adjustable mounting length – some models, including some CLAGE products, specify the maximum thickness of the mounting surface for which they are suitable in their technical specifications.
Wall-mounted faucet instead of a deck-mounted one – this solution is becoming increasingly popular with countertop basins, as it completely bypasses the problem of thickness.

Spout height – why faucet height matters

Spout height (usually stated as "faucet body height" or "spout axis height above the mounting surface") directly affects the comfort of use. A faucet that is too low – the hand cannot reach under the spout. A faucet that is too high – water splashes out of the basin, and if there is a cabinet above it, the faucet hits it.

Approximate values for common types of basins:

Classic undermount basin (depth of the basin part 120–160 mm): spout height above the basin edge should be 100–180 mm, faucet height 150–220 mm.
Half-mounted and countertop basins (depth of the basin part 80–120 mm): faucet height 180–260 mm, or even a taller deck-mounted faucet.
Basins on a pedestal: faucet height depends on the design of the basin part, standard heights are usually sufficient.
Kitchen sinks: spout height 200–280 mm, arm length 200–230 mm – to reach even the back wall of the sink.

Even more important than the absolute height of the faucet is the clearance above the faucet. If you have a wall cabinet above the basin, measure the distance from the mounting surface to the bottom of the cabinet and subtract at least 30–40 mm for clearance. This will be your maximum acceptable faucet height.

Length of the spout arm and reach over the sink/basin

The length of the arm (horizontal distance from the faucet axis to the spout axis) is crucial especially for kitchen faucets. For bathroom basins, the arm should direct the spout approximately to the geometric center of the basin part – not too far back (water runs down the back wall and drips on the sides), nor too far forward (water splashes out).

Practical arm length values:

Bathroom basin faucets: 80–130 mm (short arm, spout pointing straight down or slightly forward)
Kitchen sink faucets: 180–250 mm (long rotating arm to handle the entire sink)
Bathtub faucets with shower: arm length can be 150–200 mm, but it also depends on whether the faucet is deck-mounted or wall-mounted
Faucets with 360° rotating arm: this solution is very practical for double sinks

When choosing a kitchen faucet, it is good to measure the distance between the faucet axis and the back wall of the sink. Ideally, the spout arm should reach at least 2/3 of this space. If the sink is 500 mm deep and the faucet axis is 100 mm from the front edge, you will need an arm of at least 200–250 mm for comfortable pot filling.

Wall-mounted faucets – different rules, different dimensions

Wall-mounted faucets (corner, wall-mounted) have a different geometry. Here, the spacing in the basin is not measured, but the position and height of the wall connections are key dimensions. The standard spacing of the connections is again 150 mm (axis–axis), but the height of the connection axis above the floor or above the basin edge is a key dimension.

For wall-mounted basin faucets, the connection axes should be positioned so that the faucet body is at an ergonomically comfortable height. Typically, the wall connections are installed 900–1050 mm above the floor for basin faucets, and 700–900 mm for bathtub faucets with a filling spout.

A very important detail for wall-mounted faucets: depth of embedded corner brackets. Most wall-mounted faucets assume that the connection necks protrude from the wall (after plastering) by a certain amount – typically 10–15 mm. If the necks are embedded too deeply, the faucet does not sit fully against the wall and a visible gap will appear between it and the wall. If they protrude too much, you cannot mount the faucet body in the correct position. The manufacturer always specifies the required depth of embedding in the installation instructions – this is one of the things you should pass on to the mason/plumber before they start plastering.

Flexible hoses – length, diameter and type of ending

Flexible hoses are the link between the tap connections and the wall or floor supply lines under the sink. Although it may seem like a minor detail, choosing the wrong hoses can complicate the installation.

Length of flexible hoses

The standard packaging of most freestanding taps includes flexible hoses 300–400 mm long. This is sufficient in cases where the supply lines are directly under the sink in the wall or in the floor. If the supply lines are at a greater distance (e.g., during a renovation where the supply lines remain in their original position and the new sink is shifted), you will need longer hoses – 450, 500 or even 600 mm.

Never bend flexible hoses into sharp angles or stretch them to their maximum reach. In both cases, their lifespan is reduced and the risk of bursting increases. The ideal bend radius is at least 50 mm.

Endings of flexible hoses

The most common combinations of endings:

G½" × G½" – the same thread on both ends, standard for most situations
G⅜" × G½" – if the tap has G⅜" connections (less common, but occurs)
Angled vs. straight endings – angled endings are common for connections coming out of the wall behind the sink, while straight or T-pieces with shut-off valves are used for connections coming out of the floor

Practical scenarios from real life – what breaks most often

Scenario 1: Bathroom renovation, sink remains

The customer wants to replace an old two-handle tap with a modern single-lever one. The old sink has three holes – for both taps and for the drain – spaced 150 mm apart. The new single-lever tap has one mounting hole. Solution: buy a single-lever tap with cover plates or side covers for the additional holes. Many manufacturers, including CLAGE, offer these covers as accessories with the taps. The result is a clean look and the installation does not require modifying the sink.

Scenario 2: New countertop sink made of stone imitation

The customer buys a designer bathroom furniture with a countertop sink of 45 mm thickness. A standard tap has a mounting nut suitable for thickness up to 30 mm. Result: the nut cannot be tightened. Solution: an extended mounting rod (sold separately) or a tap specifically designed for thicker mounting surfaces. When buying such a sink, always check the maximum thickness of the mounting surface in the tap's specifications.

Scenario 3: Old installation with non-standard spacing

In panel apartment installations from the 80s, we sometimes encounter a spacing of 120 mm or even completely non-standard values. In such cases, the only solution is to re-install the supply lines so that they fit a standard tap – or to use flexible supply hoses of sufficient length that can absorb the deviation. Another option is to leave the supply lines as they are and use elbows to shift the connections to the correct spacing of 150 mm.

Scenario 4: Replacement of a bath tap, changing from a freestanding to a wall-mounted one

The customer wants to switch from a freestanding bath tap (mounted on the edge of the bath) to a wall-mounted one. This requires modifying the installation – the connections must be embedded in the wall at the correct height and with the correct spacing. Coordination between the tap selection and construction work is essential. The tap must be selected before the mason embeds the installation, and the installation plan with dimensions must be handed over to the plumber.

How to read a tap technical sheet – where to find all the necessary dimensions

Every manufacturer (including CLAGE) provides a technical sheet or mounting drawing with the taps. Learn how to read it – it will save you a lot of problems. A typical technical sheet includes:

Product dimensions – height, width, depth (arm projection), sometimes also a 3D view with dimensions
Mounting diagram – diameter of the mounting hole, maximum thickness of the mounting surface, length of the mounting thread
Spacing of connections – center to center in mm
Type and size of connection thread – G½" internal/external
Length of supplied flexible hoses
Working pressure and flow rate – more about this in the article Water flow and pressure – which CLAGE tap parameters you need

Technical sheets are usually available on the manufacturer's website or directly with the products in the online shop. If you are unsure about specific dimensions, download the PDF mounting drawing – it is a much more reliable source than a product photo, where proportions may be distorted.

Table: Overview of standard dimensions by tap type

Tap type	Connection spacing	Hole diameter	Tap height (approx.)	Arm length (approx.)
Single-lever basin tap (freestanding)	150 mm	32–35 mm	150–220 mm	80–130 mm
Two-handle basin tap (three-hole)	150 mm	3× approx. 30 mm	120–180 mm	80–120 mm
Single-lever kitchen tap	150 mm	35–40 mm	200–350 mm	180–260 mm
Freestanding bath tap	150 mm	2× approx. 30 mm	180–260 mm	150–200 mm
Wall-mounted bath tap	150 mm (in the wall)	—	700–900 mm (height of the axis in the wall)	150–200 mm
Wall-mounted shower tap	150 mm (in the wall)	—	900–1050 mm (axis in the wall)	—

Selecting a Faucet Based on Dimensions – Step by Step

If you want to be sure before placing an order, follow this procedure:

Measure the center-to-center distance of the connections – in mm. Check if it is 150 mm (standard) or another value.
Check the type of mounting – deck-mounted (how many holes in the sink?) or wall-mounted.
Measure the diameter of the hole(s) in the sink – compare with the mounting parameters of the faucet.
Measure the thickness of the mounting surface – the edge of the sink, ceramic, or countertop. Compare with the max. thickness in the faucet's technical data.
Measure the height of the available space above the faucet – from the mounting surface to the bottom of the cabinet/mirror. Subtract 30–40 mm from this number – the result is the max. height of the faucet.
Consider the length of the spout – especially for basin faucets. Measure the depth of the sink and the distance from the front edge to the center of the faucet.
Check the length of the flexible hoses – measure the distance from the bottom of the faucet connection to the connection under the sink. Add 50–80 mm of extra length for bending.

Once you have these values, compare them with the technical data of the selected faucet. If the numbers match – place your order. If you are unsure about anything, also read the articles Installation of CLAGE Water Faucet – Step by Step or How to Choose CLAGE Water Faucets – What to Pay Attention to, where you will find more details about selection and installation.

Dimensions and Design – When Aesthetics Collide with Technical Requirements

In practice, it often happens that a customer is immediately attracted by a specific faucet design – a tall free-standing faucet, a trendy matte black finish, a slim minimalist body. The problem arises when it turns out that this faucet has a spout length of only 90 mm, while the new countertop sink has a basin depth of 200 mm. The spout ends at the back edge of the basin instead of in the center. Result: water runs down the back wall of the sink, leaves limescale deposits in hard-to-reach places, and the aesthetic intention ends up being the opposite effect.

Therefore, it is important to remember: first technical parameters, then design. Or more precisely: define technical parameters as a filter and from the products that meet them, choose the most beautiful one. Not the other way around. The good news is that in the range of CLAGE water faucets, there is sufficient variety of dimensions and design lines, so with a reasonable selection process, you do not have to make a big compromise on either side.

What to Do When Standard Dimensions Do Not Fit

Sometimes, despite all the preparation, it happens that available products do not fit your dimensions exactly. In such cases, there are these options:

Adapters and thread reductions – help with incompatible thread sizes. Always buy certified adapters for drinking water, not improvised solutions.
Extended mounting rods – for problems with the thickness of the mounting surface.
Longer flexible hoses – for greater distances between the plumbing.
Corner ball valves with adjustable position – allow for a slight shift in the position of the connection axis.
Redesign of the plumbing – for significantly non-standard spacing or position of the connections. This is a one-time investment and you will avoid compromising solutions with every subsequent faucet replacement.

If you are dealing with a non-standard situation, consult it with a plumber before buying the faucet. An experienced plumber can tell you, based on a photo and dimensions, what is realistically possible without major construction changes. More about the installation process can be found in the article Installation of CLAGE Water Faucet – Step by Step.

Most Frequently Asked Questions (FAQ)

How do I measure the center-to-center distance of the connections if they are embedded in the wall and only the collars are visible?

Measure the distance between the centers (axes) of the visible collars – that is, from the geometric center of one collar to the geometric center of the other. If the collars are round, the center is simply their axis of symmetry. Use a steel tape measure or a sliding caliper. If access is difficult, you can also measure using two pencils placed against the collars and measure the distance between them – then add the radius of one collar on each side (or measure from edge to edge and add one collar diameter).

Can I install a faucet with a 150 mm center-to-center distance on old plumbing with a 120 mm spacing?

Directly – no, the faucet connections do not align with differently spaced plumbing. The solution is either to rework the plumbing (a permanent solution) or to use extended flexible hoses with sufficient flexibility and length that can absorb a 30 mm deviation on each side. In practice, flexible hoses of 400–500 mm usually handle this deviation, although the result may not be aesthetically ideal. If possible, I recommend reworking the plumbing.

What does it mean when a faucet has a "height of 180 mm" – is this the height of the entire body including the spout?

The height of the faucet in the catalog usually refers to the height of the body from the mounting surface (edge of the sink) to the highest point of the faucet body – which is usually the axis of the lever or the top part of the body. The height of the spout axis (where the water flows) may be lower. The horizontal extension of the spout is a separate dimension (spout length). Always check the technical data to confirm which dimension corresponds to which measurement – manufacturers sometimes label them differently.

Flexible hoses are included in the package – do I need to replace them, or can I use the old ones?

If the old flexible hoses are not visibly damaged, not corroded, and are not older than 8–10 years, you can reuse them when installing a new faucet – provided they have a compatible thread. Always replace the seals (flat rubber rings), which are included in the new faucet package, or buy them separately. Old seals lose elasticity after long-term use and can cause dripping. If the hoses are damaged, the braiding is torn, or visible corrosion is present – always replace them. This is not just about aesthetics, but also about safety.

How can I determine the diameter of the hole in my sink without removing the old faucet?

Most of the time, you can determine it by measuring the diameter of the round cover at the base of the old faucet body (under the extended cover at the base of the faucet) – the hole in the sink is approximately 5–8 mm smaller. Or simply: if there is a standard single-lever deck-mounted faucet in the sink, the hole is 32–35 mm. If you have doubts, check the technical data of your sink (the manufacturer usually publishes it on their website), where the hole diameter is always specified.

Is there a difference between a 150 mm center-to-center distance for a deck-mounted and a wall-mounted faucet?

Geometrically, it is the same dimension – a center-to-center distance of 150 mm applies to both deck-mounted and wall-mounted faucets. The difference is in where this distance is realized: for a deck-mounted faucet, it refers to the distance between the mounting holes in the sink or the distance between the connections under the sink, while for a wall-mounted faucet, it refers to the distance between the built-in wall connections. In both cases, the standard is 150 mm and the new faucet must match this dimension.

Conclusion: Measure Twice, Buy Once

Faucet dimensions are not something you need to address only during installation. Five minutes with a tape measure before placing an order will save you hours of problem-solving, unnecessary trips to the store, and possibly also the costs of returning goods and re-delivery. The key dimensions you always need to know: center-to-center distance of the connections, diameter and number of holes in the sink, thickness of the mounting surface, height of the available space above the faucet, and required spout length.

For most standard bathrooms, standard dimensions apply – center-to-center distance of 150 mm, one hole of 32–35 mm diameter, flexible hoses of 300–400 mm. If you have a standard sink, you can easily choose a faucet based on design and price. If you have something non-standard – a countertop sink, an old installation, or unusual dimensions – pay a bit more attention to the measurements and, in case of doubts, consult with a plumber before purchasing. The entire category of CLAGE water faucets is designed for European standards and with proper measurement, you will always find a suitable product.

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