How to Install a Tap - Step by Step Guide
Installation of a Basin Faucet – Step-by-Step Guide
Replacing or installing a basin faucet for the first time is one of those home tasks that any handy DIY enthusiast can handle – as long as they know what they're doing and have the right tools and procedures ready. In practice, however, we often see that people make unnecessary mistakes when it comes to faucets: they use the wrong sealing material, forget to close the main shut-off valve, or over-tighten the fittings and damage the threads. This guide will walk you through the correct way to do it – from preparing the tools through the removal of the old faucet to checking the tightness of the new installation.
This article is intended for standard wall-mounted faucets installed on a sink, bidet, bathtub, or washbasin. If you are considering an undermount faucet, also see our separate article Undermount vs. Wall-Mount Faucets: Which One Is Suitable for Your Bathroom – the installation procedure differs significantly and involves masonry work.
What You Will Need: Tools and Materials
Before any installation, prepare everything in advance. Nothing is worse than cutting off the water supply for the entire apartment and then spending half an hour searching the workshop for the right wrench.
Tools
- Adjustable wrench (200–300 mm) – for connections and nuts. Most domestic faucets use G 1/2" connections (external thread diameter approx. 20.9 mm), some bathtub faucets use G 3/4".
- Faucet installation wrench (also called a "basin wrench" or wrench with a long handle) – if you are installing a faucet under a sink or countertop, where access to the nut is limited.
- Screwdriver (flat and crosshead) – for mounting screws and cover plates.
- Utility knife or scissors – for cutting hose connections and sealing materials.
- Bucket or tray – to catch residual water in the pipes.
- Plastic sheet or cloth – to protect chrome surfaces from scratches caused by the wrench.
- Flashlight or lantern – the space under the sink or bathtub is usually dark.
Materials and Sealing Supplies
- Teflon tape (PTFE) – basic sealing material for metal threads. Width 12 or 19 mm, standard thickness. Wind it in the direction of the thread (clockwise when viewed from the front of the thread).
- Flat rubber seals – cylindrical gaskets for hose connections (usually included with the faucet, but keep some in stock: diameter 3/4" = approx. 18 mm internal diameter).
- Flexible hose connections (stainless steel or plastic braided, length 30–50 cm) – if not included in the package. Always check whether the package includes hoses and seals; cheaper faucets sometimes omit them.
- Silicone sealant / sealing strip under the base of the faucet – to prevent water from entering under the sink or into the furniture.
Before the actual installation: what to check
Start every installation by checking the condition of the existing installation and the new product. Opening the box and just installing the faucet is the fastest way to run into problems.
Checking the new product
Unpack the faucet and check the contents of the package: the body of the faucet, mounting nut (locknut), seals, possibly supply hoses and an installation manual. Most quality faucets – for example, wall-mounted sink faucet LOOP 946487 or wall-mounted sink faucet ARKO in satin finish – include all parts including seals in the package. Cheaper models sometimes omit the hoses.
Check the diameter of the mounting hole in the sink or washbasin. The standard diameter is 35 mm. If your hole is 32 mm or 38 mm, you will need a reducing plate, or you may need to enlarge the hole.
Checking the existing installation
Look at the connections – are they pipes (copper, stainless steel) or hoses? What thread do they have? Most domestic water supplies end with a valve with an external thread of G 1/2" (so-called "angle valve"). If you have an older installation with G 3/4" hoses, you will need a reducer. For more information on thread dimensions, see the article Dimensions and connections of faucets: what do 1/2", 3/4" and center-to-center distance mean.
Try to determine the water pressure – if you don't know it, most apartment water supplies operate within 2–5 bar. Cartridge faucets (single-lever) usually require at least 0.5–1 bar. This topic is discussed in more detail in the article What water pressure do faucets need and what to check before purchase.
Step 1 – Closing the water supply
This is the step that people most often forget or underestimate. Before making any changes to the plumbing, close the water supply. You have two options:
- Angle valve directly under the faucet – if you have separate shut-off valves for hot and cold water under the sink or washbasin, simply close them. Turn the handle perpendicular to the pipe axis (usually 90°). Check the tightness – open the faucet and the water should stop flowing.
- Main shut-off valve of the apartment / house – if you don't have angle valves or they are old and don't seal, close the main water supply. Don't turn it abruptly, but slowly.
After closing the valve, open the faucet (or the one you are going to replace) fully – this will drain the residual water from the pipes. Place a bucket or cloth under the sink.
Step 2 – Removal of the old faucet
If you are replacing an existing faucet, the next step is removal. The procedure depends on the access and type of faucet.
Disconnecting the supply hoses
Using an adjustable wrench, loosen the nuts on the hoses from the angle valve – not from the faucet itself. Let the hoses hang from the faucet if they are part of the old installation and you are not going to use them further. Have a bucket ready – water will drip from the remaining hose.
If the hoses are rusted or stuck, never apply force to bend the pipe. Use a spray such as WD-40 or another penetrant, let it sit for 10–15 minutes, and try again. A cracked copper pipe is a much bigger problem than waiting a few minutes.
Loosening the mounting nut
From the underside of the sink or basin, you must unscrew the mounting nut that holds the faucet in place. On basins with a deep undermount (e.g., ceramic undermount basins), this location is hard to reach – this is exactly why a long-handled, swivel faucet wrench is useful. Grip the nut and turn it counterclockwise (in the direction of unscrewing). When the nut loosens, support the faucet with your other hand so it does not drop.
Removing the old faucet
After loosening the mounting nut, lift the faucet upward. Remove the old sealing strip or rubber gasket from under the base – it will be dry, possibly moldy, or rusted. Clean the opening in the sink. If there is old silicone residue on the base, carefully cut it off with a knife and mechanically remove the rest (be careful with the sink surface).
Step 3 – Preparing the new faucet before installation
Before inserting the new faucet into the opening, you must prepare the sealing under the base. You have two options:
- Rubber sealing washer – most faucets include one in the packaging. Place it under the base of the faucet. If you are placing the faucet on a ceramic sink or stone, this washer will be sufficient.
- Clear silicone – if you are mounting on wood, cabinetry, or an uneven surface, apply a thin bead of silicone around the edge of the opening from the top before installing the faucet. This prevents water from getting under the base and causing mold.
If you choose silicone, make sure it is suitable for bathrooms (resistant to moisture). Do not use acrylic silicone on metal – it releases acetic acid, which corrodes brass components.
Step 4 – Installing the faucet into the opening
Insert the body of the faucet through the opening from above. If the faucet has a mounting tab or an arrow on the base indicating orientation (e.g., for faucets with side outlets), make sure to rotate it correctly toward the sink.
From the underside, slide on the mounting washer (if included) and then the mounting nut. First, screw the nut on by hand – turn it clockwise (in the direction of tightening). When the nut is seated, tighten it with a wrench. The rule here is: tighten firmly, not forcefully. The brass thread of the faucet in a plastic nut can be easily damaged by excessive force. The recommended tightening torque for G 1/2" is approximately 15–20 Nm – this is about the force you exert when tightening a wrench well with one hand without using an extension.
Step 5 – Connecting the water supply (supply hoses)
This is the step where the tightness of the entire installation is decided. Supply hoses connect the faucet to the angle valves under the sink. They have two connections – one for hot water (usually marked red or with the letter H – hot), and one for cold water (blue or C – cold). Never mix them – the internal parts of the cartridge are designed for the correct temperature orientation.
Wrapping Teflon tape
Teflon tape is wrapped only on metal threads – that is, on the external thread of the angle valve, not on the hose thread. Procedure: grasp the beginning of the tape, place it on the thread, and wrap it in the direction of the thread (clockwise, if you are looking at the thread from the front). Number of wraps: 3 to 5 layers are sufficient. The tape must not be too dense – too many layers can cause the plastic nut to crack or prevent proper seating.
Important: do not use Teflon tape on connections where there is a rubber flat gasket (e.g., at the hose inlet into the faucet). The sealing is either one or the other – not both at the same time. The rubber washer forms a flat seal and the tape would lift it, which would compromise the tightness.
Tightening the hoses
First, manually screw the hose into the angle valve (check that it is straight – no cross-threading). Then tighten it with a wrench. Again, the rule applies: firmly, but not forcefully. For G 1/2" hoses, the recommended torque is approximately 10–15 Nm. The hose nut is usually made of brass or chrome-plated brass – be careful that the wrench does not slip and scratch the surface. Hold the body of the faucet with your other hand or with a cloth – this prevents it from rotating during tightening.
At the other end of the hose - at the faucet - there is usually a flat rubber gasket. Tighten it firmly, but do not bend the hose. Flexible hoses have an internal rubber reinforcement and can crack after years of extreme bending. Route the hose with a slight curve, not sharply bent.
Step 6 - Leak Test and First Start-up
Before finally opening the water shut-off valve, visually check all connections once again. Then slowly and carefully open the angle valve - not fully, just slightly. Watch the connections and nuts. If nothing drips, open it fully.
Open the faucet and let the water run for a while - air bubbles and possibly small impurities from the installation may come out of the pipe. This is normal with every new installation. After 30–60 seconds, turn the water off and dry all connections thoroughly. Wait 5 minutes and check again - sometimes a small leak only becomes apparent under pressure.
If a connection is dripping, do not force it dry immediately. Shut off the water, loosen the connection, check the gasket, and tighten again. A violent struggle with a dry, stuck piece of Teflon and a seized nut is certainly more unpleasant than calmly fixing the error with a drained pipe.
Mounting specifics according to faucet type
Countertop Faucet
The most common type - mounted from above into the sink hole. The standard hole is 35 mm, the distance between the hot and cold connections is usually 150 mm (= 1/2" BSP). The faucet has a rubber gasket under the base, and a nut with a washer is tightened from below. The hoses are usually 30–40 cm long and lead down to the angle valves. An example of such a product is the ARKO countertop faucet in satin finish - an elegant satin brass finish suitable for a more modern style of bathroom or kitchen.
Basin Faucet
The procedure is the same as for the countertop faucet, the difference is in the length of the spout and the height of the faucet body. Important: basins have different ceramic thicknesses (15–25 mm) and sometimes the space under the basin is very limited. For deep basins (undermount, semi-recessed), you will need the mentioned mounting key with an extension.
Bidet Faucet
Bidet faucets are mounted directly on the bidet - again a 35 mm hole, standard G 1/2". Special features include a drain set (trap with a lift) and sometimes a metal rod of the drain valve running through the body of the faucet. With the ARKO bidet faucet with drain set in chrome finish, the complete drain set is included in the package - it must be connected according to the attached installation manual before mounting the faucet. The chain (rod) passes through the hole behind the spout and must be adjusted so that it smoothly controls the drain. Similarly, the ARKO bidet faucet in satin finish is mounted - the same system, different surface.
Drain set installation procedure: first insert the trap plug into the bidet drain, secure it with a rubber gasket, and tighten the drain nut from below. Then thread the control rod through the top hole of the faucet, mount the faucet, tighten the locknut, and finally adjust the rod so that when the faucet handle is pulled up, the plug sits in the drain and when pressed down, it is lifted.
Bathtub Faucet
Bathtub faucets are mounted either on the tub rim (2 holes, center distance 150 mm), or on the wall. For a bathtub faucet with accessories (shower hose, head, holder), it is necessary to have the correct center distance between the holes - usually 150 mm (sometimes 180 mm). Checking this before purchase is critical. You can read more about this in the article Dimensions and connections of faucets: what do 1/2", 3/4", and center distance mean.
A bathtub faucet without accessories - for example, the ARKO bathtub faucet in satin finish, without accessories - is mounted similarly to a countertop faucet: through the holes in the tub, the locknuts are tightened from below. The advantage of the "without accessories" version is the lower price, if you are solving the bathtub shower separately or have kept it from the old set.
Common installation mistakes - and how to avoid them
Mixing up hot and cold water
The connections must not be mixed up. A cartridge faucet has internal parts oriented so that hot water comes in from the left (when you stand in front of the faucet) and cold from the right. If mixed up, the cartridge will react incorrectly to the handle rotation and may result in damage to the rubber gasket of the cartridge due to high temperature at the wrong location.
Over-tightening - cracked nut or thread
Very common among DIYers. Brass threads can withstand surprisingly much, but plastic locknuts or hose nuts are more sensitive. When you feel resistance and the nut "seats", further turning of the wrench can only cause damage. If the connection still leaks after a firm tightening, the problem is in the gasket - not in the insufficient torque.
Forgotten gasket
It happens: the hose is tightened without the rubber washer and a drop appears immediately after starting the water. Solution: unscrew, install the gasket, and tighten again. Always check that the gasket is in place before you start screwing.
Teflon tape applied in the wrong direction
If you wrap the tape against the thread direction, it will unwind during tightening instead of sealing. Rule of thumb: always wrap it as if you were tightening a nut – that is, in the direction of the thread closure.
Scratching the tap surface with pliers
This applies especially to satin and black matte finishes, which are more sensitive than chrome. Always wrap the pliers jaws with a cloth, electrical tape, or use pliers with plastic jaws. This is especially important for ARKO satin taps – the fine brushed surface scratches more easily than mirror chrome. For more information on tap finishes, read our article Tap Surface Finishes: Chrome, Satin, Black Matte – Differences and Durability.
Installation in special conditions
Mounting on thick stone or ceramic countertops
If you are installing a tap on a stone (granite, quartzite) or thick ceramic kitchen countertop, the standard backnut may be too short. Manufacturers often provide extended threaded rods or longer backnuts to solve this. Always check the mounting thickness (called "deck thickness") stated in the technical data sheet of the tap – usually 20–50 mm. If your countertop is thicker, contact your supplier.
Connecting to pipes without angle valves
Older installations sometimes lack angle shut-off valves – the water supply comes directly from the wall through a rigid copper pipe. In such cases, you must either install an angle valve (which requires modifying the installation, ideally with the help of a plumber), or use special connecting pieces with built-in shut-off valves. Working on an installation without shut-off valves under the tap is risky in the long run – any problem (a broken cartridge, a leaking hose) means water all over the apartment with no way to quickly shut it off.
When to call a plumber
Replacing a tap is usually a simple task. However, there are situations when it is better to leave it to a professional:
- The threads of the angle valves are damaged or corroded and do not seal even after replacing the hoses.
- You are installing an undermount (built-in) tap – this requires cutting into the wall, proper embedding, and setting the installation depth according to the tile thickness.
- The water pressure in your home is too low or too high (below 0.5 bar or above 6 bar) – this is an issue with the entire installation, not just the tap.
- You notice corrosion or damage in the piping behind the wall.
- Old pipes are made of lead or old plastic (PVC) and require replacing the entire section.
Frequently asked questions (FAQ)
Do I need to turn off the water for the whole house when replacing the tap, or is it enough to just turn it off under the sink?
If you have angle valves (angle taps) in good condition under the sink or basin, it is enough to turn them off. To check this, close them and then open the old tap – if the water stops flowing, the angle valves are sealing. If you don't have angle valves or they are damaged, you must turn off the main shut-off valve. In apartment buildings, the apartment shut-off valve is usually located in the hallway in the riser shaft or in the entrance area of the apartment.
What sealing should I use between the tap and the sink?
Most taps come with a rubber sealing washer under the base – this is the primary seal. For wooden or composite kitchen countertops, I recommend additionally applying a thin bead of clear silicone around the base before installation. For ceramic sinks or basins, the rubber washer is usually sufficient on its own.
Can I reuse the old connecting hoses if they still look in good condition?
Be cautious. The internal rubber reinforcement of the hose ages and cracks even without visible signs. If the hoses are older than 10 years, I recommend replacing them – new ones cost just a few euros and are cheaper than a flooded bathroom. When buying a new tap, check whether the hoses are included in the package.
After installation, the water coming out of the tap is cloudy or has air bubbles. Is this normal?
Yes, this is normal and usually lasts only a few seconds to minutes. Every new installation or tap replacement introduces air into the piping. Simply let the water run fully for about a minute until the piping is cleared. If the cloudiness persists for a long time, it may be sediment from old pipes – this is a separate issue unrelated to the tap installation.
The tap drips from the outlet after installation. Is this a problem with the installation?
No – dripping from the outlet (spout) after closing the tap is not related to the installation of the connections. It is an issue with the cartridge or valve seal inside the tap. If you bought a new tap and it immediately drips, return it. If the tap is older, replacing the cartridge usually helps. See our article Replacing the seal and cartridge in a tap: when and how to do it.
What length of connecting hoses should I buy?
Measure the distance from the bottom end of the tap (where the thread is or the existing hose) to the angle valve on the wall or under the sink. Common lengths are 30, 40, 50, and 60 cm. Always buy 5–10 cm longer than the measured distance – the hose must have a slight curve and must not be stretched. A stretched hose under pressure is a time bomb waiting to burst and flood your bathroom.
Conclusion
Installing a water tap is a 30–60 minute job that any DIY enthusiast can handle with basic tools, provided the procedure is followed correctly. The key is thorough preparation (correct tap, correct seals, water turned off), precision in sealing the threads, and patience during leak testing. Do not underestimate any of the steps – every detail, from the correct direction of the teflon tape to checking the seal under the base, determines whether your installation will work trouble-free for years or whether you will be fixing it in a week.
If you are unsure about choosing the right tap for your space and installation, also read our articles How to choose taps for your bathroom and kitchen and Differences between sink, bath, shower, and bidet taps – they will help you choose the right type even before installation.
Do you have a question about this topic?
Struggling to decide or dealing with a specific situation in your home? Write to us – we're happy to help.