Dimensions and connections of Opera batteries: what to check before purchase

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Dimensions and Connection of Opera Taps: What to Check Before Purchase

It seems simple – you buy a new tap, unscrew the old one, install the new one. In practice, it doesn't always work that way. Hundreds of customers order taps every year that either don't fit into the sink, have a different hole spacing than the installation, or can't be connected without unnecessary reconstruction of the entire plumbing. The bathroom is disassembled, the family is waiting for water, and the plumber bills for every extra hour. Yet it's enough to measure five things and verify three parameters before purchasing.

This article will guide you through everything you need to know about the dimensions and connection of Opera taps – from the diameter of the holes in the sink and the spacing of the connections to the height of the spout, the angle of the lever rotation, and the types of threaded ends. You will find specific numbers, diagrams, and practical examples based on real installation practice.

Why tap dimensions are critical even before ordering

The Opera tap is a high-quality product with a long lifespan, but even the best tap won't help if it doesn't physically fit into your bathroom or kitchen. There are three scenarios that repeat when the wrong dimensions are chosen:

The tap doesn't fit into the sink or basin hole – either the body of the tap is too thick, or the mounting nut doesn't reach the underside of the basin.
The water inlet spacing doesn't match the installation – especially with Opera two-hole taps or basin taps with side connections.
The spout height is too low or too high – water sprays outside the sink, or the tap doesn't look proportionate to the sink and the space.

All three situations can be avoided. Let's proceed systematically.

Mounting hole diameter: a standard that is not always the same

The most common hole for a single-lever tap in a bathroom or kitchen sink has a diameter of 35 mm. This applies to the vast majority of Opera taps from the bathroom and kitchen series. Some models with a more massive body require a hole of 38 mm, which is a less common dimension – it occurs mainly with thermostatic taps or premium series with a larger body diameter.

When replacing an old tap with a new one, measure the diameter of the existing hole before ordering. If the hole is larger, it can be solved with a decorative cover ring (rosette), which is part of the package for most Opera models. If the hole is smaller than the body of the new tap, it needs to be enlarged – in the case of a ceramic sink, this is a more complicated intervention requiring a diamond drill and patience.

Practical tip from practice: if you are buying a tap for an older sink from the 80s or 90s, check whether it has a standard hole. Many old Czechoslovak products had holes of 32 mm or even 30 mm, which are not compatible with any standard Opera tap today without modification.

Thickness of the sink or basin top: what the mounting nut is for

Fewer people think about the thickness of the plate through which the tap is mounted. The mounting nut must reach the underside of the plate and securely clamp it. Most Opera taps have a mounting nut reach of 20 to 60 mm, which covers standard ceramic sinks (edge thickness typically 10–18 mm) and kitchen granite or solid surface (thickness 30–50 mm).

Problems arise with:

Very thick kitchen tops – for example, massive granite or technical stone 60–80 mm thick. Here, you need to extend the mounting part or choose a tap with a longer passage.
Very thin ceramics – modern "slim" sinks with an edge of only 5–8 mm. The mounting nut will reach, but you need to be careful not to crack the ceramic with the force.
Metal basins with ribs – the rib can prevent the nut from tightening, so a washer with a cut-out is needed.

Always measure the thickness of the plate at the hole location before installation. Not at the edge, but directly where the tap will go – the thickness may not be the same across the entire surface.

Water inlet spacing: 150 mm, but not always

This is a parameter that causes the most trouble when replacing old taps with new ones, or when installing in a new bathroom where the plumber or mason made the layout according to their own judgment.

The standard water inlet spacing for Opera bathroom and kitchen taps is 150 mm center to center. This applies to:

Single-lever tap for the sink (supply from below via flexible hoses)
Kitchen tap with the same connection system
Most shower and bathtub taps with side connections

Deviations from 150 mm exist and are more common than you might think. Old installations from before 1990 have very varied spacing – 120 mm, 130 mm, 160 mm, sometimes even 180 mm. Modern installations are done according to standards, but a deviation of 10–15 mm can happen.

How are deviations in spacing resolved? Flexible supply lines (flexible hoses), which are part of the packaging of most Opera taps, usually have enough flexibility to accommodate a deviation of 10–20 mm without any problems. If the deviation is greater, corner valves with adjustable position or S-links are used to compensate for the larger spacing. It is ideal, however, to set the correct distance already during the installation of the piping – this will save complications.

Types of connections for Opera taps: threads and their behavior in practice

Most Opera taps are connected to the water supply system via threaded connections. It depends on where you are in the installation:

Connection to the installation (wall / floor)

Outlets from the installation are usually equipped with an external thread G 1/2" (sometimes also marked as BSP 1/2" or ½ inch). A corner valve is connected to this thread, and water is led to the tap via a flexible hose. This is the absolute standard in Slovakia and the Czech Republic, and Opera taps are fully compatible with it.

For bath taps and shower taps with a higher flow rate, the outlet G 3/4" occasionally occurs, but in a standard bathroom you will find it only rarely – more often with old cast iron baths with massive corner valves.

Connection to the tap (inlet into the body of the tap)

Opera taps have inlet nozzles with an internal thread G 1/2". Flexible hoses or corner valves (if the tap is close to the wall) are screwed onto this thread. The sealing is either flat (rubber washer) or conical seating – check which sealing system the respective Opera model uses, so that you do not use the wrong sealing during installation and thus cause a leak.

Flexible hoses: length and diameter matter

The flexible supply lines that connect the corner valve to the tap are part of the packaging for most Opera models. Their standard length is 300 mm or 350 mm. If the distance from the corner valve to the tap is greater (for example, deep cabinets under the sink or a non-standard position of the outlet), you will need longer hoses – 400 mm, 500 mm or even 600 mm.

The diameter of the flexible hoses corresponds to the thread: common are hoses with both ends G 1/2" (mostly nut x nut). When selecting, check the braiding material – brass or stainless steel. Plastic braiding (sometimes referred to as "PVC braiding") is a cheaper alternative, but it may become brittle under long-term load and at higher temperatures. For Opera taps, we recommend stainless steel braiding with an EPDM inner hose.

Outlet height and reach of the spout: why it should be measured in advance

Outlet height (from the base of the tap to the center of the spout) directly affects both the functionality and the aesthetics. An outlet that is too low means you cannot place a large pot or your hands under the tap without splashing water. An outlet that is too high looks disproportionate and, with a higher flow, water may spray outside the sink.

Approximate values for common use:

Basin tap – outlet height is usually 100–160 mm from the base. For shallow sinks (basin depth up to 120 mm), choose a lower outlet, for deep sinks (basin depth 150 mm or more), choose a higher one.
Kitchen tap – outlet height 200–280 mm, or even more for high Opera models with swivel or flexible spout. Kitchen sinks are deeper and you need room to maneuver.
Bath tap – outlet height from the floor or from the edge of the bath depends on the specific model and the mounting method (standing, wall-mounted, edge-mounted).

Reach of the spout (horizontal distance from the axis of the tap to the center of the outlet) is equally important. If the sink is small and the tap has a long spout, the outlet will point outside the basin. If the sink is deep or asymmetric, a longer spout is needed so that the water falls into the center of the basin and not on the edge. Standard Opera basin taps have a spout reach of 100–130 mm, kitchen models can have up to 180–240 mm.

Mounting distance from the wall and lever movement

This is a parameter that almost everyone forgets when installing a tap close to the wall or the side of a kitchen unit. The lever (or rotating handle) of an Opera tap turns sideways and up/down. If the tap is installed too close to the wall, the tile or the side of the cabinet, the lever will hit an obstacle before it is fully opened. Result? You will not achieve full flow, or you will have to move the tap.

A standard single-lever Opera tap needs at least 80 mm of free space from the axis of the tap to the nearest obstacle on the left and right. For taps with a longer lever or with a larger angular reach, this value can be 100–120 mm. When installing a tap in a corner or near a wall, always think about this space in advance.

If the space is limited, there are Opera taps with side control or with a lever with a limited angle of movement, which is an elegant solution rather than a compromise installation of a standard tap in an unsuitable location.

Opera shower taps: spacing and height of the wall connection

Opera shower and bath taps (wall-mounted) are mounted directly to the wall and their placement is determined by the position of the prepared outlets. There is no room for improvisation here – the outlets are embedded in the plaster or covered in the tiling. Therefore, if you are doing a reconstruction from scratch, these dimensions must be specified to the craftsman before tiling.

Standard parameters for a wall-mounted Opera shower tap:

Spacing of the outlets: 150 mm center to center (hot and cold)
Height of the tap from the floor in the shower area: usually 900–1100 mm (depends on the user's height and ergonomics)
Depth of the outlets: such that the external thread G 1/2" protrudes 10–15 mm from the surface of the tiling – the tap must rest tightly against the tiling with the cover disc without any gap

If the outlets are set in too deep (for example, behind thick tiling), extension nipples G 1/2" are required. If they protrude too much, the faucet does not lie flat against the tiling and a gap forms where water and mold can collect.

Opera Bathe Taps: Floor-standing vs. Wall-mounted vs. Edge-mounted Installation

With the Opera bath tap, you may encounter three basic installation methods, each with different dimensional and connection requirements:

Floor-standing Bath Tap (Floor-mounted)

It is mounted on the floor next to the bath. It has its own base, through which the flexible supply lines run to the floor outlets. The standard distance between the outlets is 150 mm, and the outlets are located in the floor. The advantage is visual elegance and easy access, while the disadvantage is that you must install the outlets in the floor before tiling.

Wall-mounted Bath Tap

Typically mounted at the head of the bath, directly into the tiling. It has the same dimensions as a shower tap – a distance of 150 mm between the outlets, and a height of 150–200 mm from the top edge of the bath (depending on the model and the height of the bath rim).

Edge-mounted Tap (Mounted on the Bath Rim)

Less common, but available. The tap is mounted directly into an opening in the bath rim, just like a sink tap. The opening in the bath rim is usually 35 mm in diameter. The supply lines run through the hollow rim of the bath to the side connections.

What is included in the Opera tap package and what you need to purchase separately

Many customers assume that buying a tap means having everything. In reality, it depends on the specific model and installation method what is included. For Opera taps, the following is generally true:

The tap itself – always included
Flexible supply lines 300–350 mm (pair) – included in most sink and kitchen models, but not always. Check the product description.
Seals and mounting accessories – most Opera models include seals, a mounting bracket, and a key (mounting rod).
Decorative cover (rosette) – only included in some models, especially wall-mounted taps.
Aerator – part of the spout, usually pre-installed.

What you usually need to purchase separately:

Angle valves (shut-off valves) – if they are not yet installed in the plumbing. We recommend chrome-plated brass angle valves with ball valves.
Longer flexible hoses – if the distance is greater than the standard length included in the package.
Teflon tape or hemp sealing – for sealing the threads on the angle valves (not needed for flexible hoses with flat sealing).
Extension nipples – if the wall outlets are set in too deep.

If you are unsure what is included in the package of a specific Opera model, check the product description on atria.sk in the Opera category, where this information is listed for each tap. You may also read the article Step-by-step installation of the Opera water tap, where the process, including a list of required tools and materials, is described in detail.

Water pressure and flow: technical parameters that affect your choice

Along with physical dimensions, there are also technical parameters that must match your plumbing system. Opera taps are designed for standard household water pressure, but you should verify the following:

Minimum operating pressure: most Opera taps operate from 0.5 bar. Some thermostatic models require at least 1.0 bar. If you have a gravity-fed water heater (boiler in the attic), the pressure may be lower and not all taps will function properly.
Maximum operating pressure: standard 10 bar. In apartment buildings with direct connection to the water supply, the pressure may occasionally reach 6–8 bar – which is normal. If the pressure is higher, a pressure reducer is needed for the entire installation.
Maximum temperature: Opera taps are designed for normal hot water temperature up to 90 °C, which covers all common hot water sources including flow heaters.

Learn more about how the aerator and ecological flow restrictor work in the article Opera taps with water saving: how the aerator and ecological restrictor work.

Emergency solutions when the dimensions do not match: what can be saved and what cannot

It happens. The tap arrives, you start installing, and something does not fit. From experience, we know what can still be saved and where the limit is:

What can be saved:

Connection spacing ±20 mm – longer flexible hoses or S-connectors
Outlet set in too deep – extension nipple G 1/2"
Too large a hole in the sink – decorative rosette (cover)
Short flexible hoses – replace with longer ones, same thread

What cannot be easily saved:

Too small a hole in the sink – requires diamond drilling or a new sink
Connection spacing ±50 mm or more – requires plumbing system reconstruction
Wrong type of tap (e.g., floor-standing instead of wall-mounted) – requires replacing the tap

If you find yourself in this situation, we recommend reading the article Common problems with Opera taps: dripping, weak pressure, corrosion, where there are also issues related to installation and incorrect connection.

Checklist before purchasing an Opera tap

We summarize it into specific points that you can check off before clicking "Add to cart":

☐ Diameter of the hole in the sink/basin: measured in mm
☐ Thickness of the countertop at the hole location: measured in mm
☐ Water supply spacing: measured center to center in mm
☐ Type of outlet from the installation: external thread G 1/2" (to be verified)
☐ Length of required flexible hoses: measured from the elbow to the hole in mm
☐ Free space for handle movement: minimum 80 mm from the center of the faucet to the wall
¼ Desired height of the spout: adjusted to the depth of the sink or basin
☐ Desired reach of the spout: adjusted to the width of the sink
☐ Water pressure in the household: above the minimum pressure required by the faucet (0.5 or 1.0 bar)
☐ Contents of the package: verified, what is included and what needs to be purchased separately

This list is not unnecessarily bureaucratic. It is based on real-life situations where customers returned the faucet because they forgot to check one or two items. Five minutes of measuring at home will save you hours of complications during installation.

Frequently Asked Questions (FAQ)

What is the standard water supply spacing for the Opera faucet for a sink?

The standard spacing is 150 mm, measured center to center between the hot and cold water inlets. Most modern installations in Slovakia and the Czech Republic are made according to this dimension. If you have an older installation, we recommend measuring the spacing physically before ordering the faucet, as older piping may have a different spacing. Deviations of up to ±20 mm are usually compensable with flexible hoses.

The diameter of the hole in my sink is only 32 mm. Can I install the Opera faucet?

Standard Opera faucets require a minimum hole size of 35 mm. A 32 mm hole is too small – the body of the faucet will not fit through. A solution is to enlarge the hole using a diamond drill bit (for ceramic sinks), which is technically possible but requires an experienced craftsman and the right tools. Alternatively, consider replacing the sink with a new one that has a 35 mm hole.

The flexible hoses in the package are 300 mm long, but my distance is 420 mm. What should I do?

Simply purchase flexible hoses of the appropriate length – for example, 450 mm or 500 mm. The thread is the same (G 1/2" female × G 1/2" female), so compatibility is not an issue. Pay attention to quality – we recommend hoses with stainless steel braiding and EPDM inside, not cheap plastic alternatives.

Can I install a wall-mounted shower faucet Opera if my wall outlets are 130 mm apart instead of 150 mm?

Opera faucet connections usually have a fixed spacing of 150 mm and cannot be adjusted mechanically. A deviation of 20 mm (130 mm instead of 150 mm) is too large for standard brass rigidity to handle. The solution is to use S-connectors (offsets) with adjustable spacing, which are screwed into the wall and the faucet is mounted on them – these compensate for the spacing and the deviation from the wall plane. They are commonly available and often used by plumbers.

How can I determine if I have enough space for the movement of the Opera faucet handle?

Measure the distance from the planned center of the faucet hole to the nearest wall or obstacle (side of the cabinet, wall, partition). This distance should be at least 80 mm on each side. If it is less, either choose a faucet with a shorter handle or consult the supplier about a model with side or rear control. For Opera kitchen faucets, this space is less critical, as they are usually installed in a larger open area.

The Opera faucet has an inlet thread of G 1/2" – is this the same as my old elbow valve with G 1/2"?

Yes, G 1/2" is a standard thread and both the elbow valves and Opera faucets are compatible. The only thing to be careful about is the type of sealing on the flexible hose. If the hose has a flat rubber gasket (which is standard), do not add Teflon or hemp to the thread – the gasket provides the seal, not the thread. On the other hand, if you are connecting with a hose with a conical gasket (less common), Teflon on the thread is not suitable.

Conclusion: Measure first, buy after

Opera faucets are designed for standard installations common in Central European bathrooms and kitchens. Most parameters – hole diameter 35 mm, spacing 150 mm, thread G 1/2" – correspond to what you will find in current construction and common renovations. Problems usually arise with older installations, non-standard sinks or installation in limited space.

The solution is very simple: five minutes with a measuring tape will protect you from unnecessary returns, extra costs for plumbers and delays in using your bathroom. Measure the hole, spacing, distance from the wall, countertop thickness and required hose length. Compare these values with the technical specifications of the selected Opera model – and you can order with peace of mind.

For further context, we recommend reading the articles How to choose Opera water taps for your bathroom and kitchen (selection by style, function and space) and Single-lever vs. double-knob Opera faucet: which one to choose (comparison of types from the perspective of control and installation). The full range of Opera faucets can be found at atria.sk in the Opera section.

Do you have a question about this topic?

Not sure or dealing with a specific situation in your home? Write to us – we are happy to help.