Installation of a Water Tap: Process, Tools, and Common Mistakes

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Installation of a Faucet: Complete Procedure, Required Tools, and Common Mistakes

Replacing or installing a faucet is one of those home tasks that most people can do themselves – as long as they know what they're doing. At first glance, it seems simple: unscrew the old one, screw on the new one. Reality is a bit different. Every year we deal with dozens of cases where a customer calls with a problem that arose precisely during installation: leaking connections, broken seals, damaged threads, and in the worst cases, a flooded bathroom due to a forgotten shut-off valve. This article is therefore written to help you complete the entire process without errors – from the first wrench to the first turn of the tap.

Before we get into the actual procedure, make sure you have the right faucet. If you are unsure about the dimensions, center-to-center distance, or type of connection, read our article Dimensions and Connections of Faucets: What do 1/2", 3/4", and center-to-center distance mean?. If you are deciding whether a wall-mounted or deck-mounted faucet is suitable for your space, see the article Wall-mounted vs. Deck-mounted Faucet: Which is Suitable for Your Bathroom?.

Types of Faucets and What Affects Installation for Each Type

Not every faucet is installed the same way. The procedure varies depending on the type – and it is precisely these differences that cause a lot of confusion. The basic classification in terms of installation is as follows:

Deck-mounted faucet (stand-type): mounted directly into an opening in the sink, countertop, or tub; has its own stand with a sealing surface
Wall-mounted faucet: attached to the wall, connection comes from the wall via elbow or straight fittings
Undermount faucet: body is embedded in the wall, installation involves working with an undermount mounting box
Tub faucet: usually wall-mounted, with a diverter for the shower; specific to the height of installation and the length of hoses
Bidet faucet: stand-type, but with an outlet for the drain assembly

In this article, we will primarily focus on the deck-mounted faucet (the most popular type for sinks and countertops) and the wall-mounted tub faucet, while the bidet faucet will be mentioned as a special case. Undermount faucets require different procedures that deserve their own article.

What You Will Need – Tools and Materials

Good preparation saves time and nerves. From experience, I know that the most common reasons for interrupting work halfway are missing seals or unsuitable tools. Prepare the following:

Basic Tools

Adjustable wrench (spanner) size 250–300 mm – for most connections in home plumbing
Socket wrench or faucet installation wrench (also called a basin wrench) – essential for installing a deck-mounted faucet, where work is done in a confined space under the sink
Flat and cross-head screwdriver – for removing old hose clamps or valves
Slip-joint pliers (e.g. Knipex Cobra) – for hoses and small fittings
Thread sealing tape (PTFE) – a basic item without which you cannot work; do not use only hemp fiber without sealant
Silicone sealant or sealing rubber under the base of the faucet
Bucket and cloth – residual water in the pipes will always drain out
Headlamp or work light – work under the sink is dark
Protective gloves – edges under the sink are sharp

Materials and Spare Parts

Elbow shut-off valves (fittings) – if you don't have them or they are damaged
Flexible connecting hoses (flexible hoses) ½" – usually in lengths of 300, 400, or 500 mm; we recommend always buying new ones with a new faucet
Flat rubber seals for hoses (strips 1/2")
Sealing gasket under the base of the faucet (rubber ring or rubber pad – most faucets include it in the packaging)
Contact spray WD-40 or penetrating oil for old/rusted connections

Before Installation: Turning Off the Water and Removing the Old Faucet

This is the step where beginners most often cause damage. Rule number one: never start unscrewing the faucet or hoses before the water is turned off. Sounds from the pipes or the fact that the water has not been used for an hour are not a guarantee that there is no pressure in the pipes.

Step 1 – Shutting Off the Water

If you have shut-off valves (fittings) under the sink, simply turn them clockwise (to the right) until they stop. Then open the faucet to let the remaining water in the pipes drain out – this will also release the pressure. If you don't have shut-off valves, or they are old and don't seal properly, you must shut off the water at the main shut-off valve of the apartment or house. In panel buildings, apartment shut-off valves are often located in the hallway or basement.

Step 2 – Disconnecting the Hoses

The hoses are unscrewed from both sides – from the faucet and from the shut-off valve. Place a bucket under the work area, because even after the water is turned off, there will still be a few deciliters of water in the hoses. If the hoses are old and stiff, don't rush – a hose broken by force can damage the thread on the shut-off valve, which is an unnecessary complication.

If the connections are heavily corroded, apply penetrating oil (e.g. WD-40) and let it work for 10–15 minutes. Never use long levers on the hoses – the threads are relatively fine and easily damaged.

Step 3 – Removing the old faucet

With a deck-mounted faucet, you need to unscrew the nut under the sink that holds the faucet in the opening. This nut is usually plastic (for cheaper faucets) or metal. You need the special faucet wrench mentioned above to unscrew it – a regular wrench simply won't fit. After unscrewing the nut and removing the washer, pull the faucet up and out of the opening.

Mounting a deck-mounted faucet – step by step

A deck-mounted faucet (also called a stand-mounted faucet) is the most popular type for sinks and basins. An example from our range is, for instance, the LOOP deck-mounted sink faucet or the ARKO deck-mounted sink faucet in satin finish. Both have standard 1/2" connections and are mounted in the same way.

Step 1 – Preparing the faucet before installation

Before inserting the faucet into the opening, connect the flexible hoses to it (if they are not already part of the unit). This is done before installation because access is very limited after the faucet is mounted. Tighten the hoses by hand and then with a wrench by an additional half turn – not with force. Note: you must always have the rubber washer in the hose adapter thread! Without it, the connection will leak.

Step 2 – Inserting the faucet into the opening

Apply a rubber gasket or silicone sealant to the bottom of the faucet base (sealing surface). Most faucets include a rubber gasket in the packaging – use that. If not, you can buy one at any larger hardware store or at atria.sk in the category of water faucets. Insert the faucet into the opening from above. Make sure of the correct orientation – the drain (spout) must point in the correct direction (usually above the center of the sink).

Step 3 – Securing the nut from below

Under the sink, slide on the metal washer and the securing nut. Tighten the nut with a special faucet wrench (basin wrench). Tightening must be even – the faucet must not be rotated during tightening. Proper tightening force: the faucet should not be able to be turned by hand, but you don't need to pull the nut with all your strength either – broken plastic nuts are a common mistake.

Step 4 – Connecting the hoses to the angle valves

Connect the hoses to the angle valves. Important: cold water on the left, hot water on the right – this is the standard according to EN 816 and EN 200, and applies to the vast majority of faucets. Before tightening, check that there is a rubber washer in each adapter connection. Tighten with a wrench, but without excessive force – a firm connection is enough.

Step 5 – Opening the water and checking for leaks

Open the angle valves (or the main valve). Let the water run for about 30 seconds – this will flush the piping system and remove air bubbles from the hoses. Then check all connections one by one: the base of the faucet, the hoses at the faucet, the hoses at the angle valve. If there is a leak anywhere, stop the faucet, identify the location, and tighten or replace the gasket. Never ignore a micro-leak – in a week it can become limescale, rust stains, or extensive damage to the cabinet.

Mounting a wall-mounted bathtub faucet

A wall-mounted bathtub faucet is connected to two wall outlets, which must have been prepared during the rough construction or renovation. An example is the ARKO bathtub faucet without accessories in satin finish. A faucet "without accessories" means that the shower set (hose, handheld shower, holder) is purchased separately – a solution if you want to combine a specific faucet with a different type of shower.

Preparing the wall outlets

The wall outlets (so-called "S-connectors" or "eccentrics") must be fixed in the wall into concrete or mortar – not just inserted. The axial distance between the outlets is standard 150 mm (for bathtub faucets). You must verify this before buying the faucet – if the distance is different (e.g. 170 or 120 mm), you need a faucet or eccentric for a different distance. More on this in the article Dimensions and connections of faucets: what do 1/2", 3/4", and axial distance mean.

Mounting procedure

Wrap Teflon tape around the eccentrics (S-connectors) – 5 to 8 turns, always in the direction of the thread. Then screw them into the wall. If there are old holes from a previous faucet, check the condition of the internal threads. Damaged threads in the wall are a serious problem – usually you need to call a plumber. Put on the sealing rings (O-rings, usually included in the faucet packaging) on the wrapped eccentrics and attach the body of the faucet. Align the faucet horizontally using a spirit level and tighten the nuts on both sides. How to properly adjust the eccentrics so that the faucet hangs parallel to the wall is a matter of practice – they are adjusted by rotating the entire eccentric before it is fully tightened.

Installation of a bidet faucet with drain kit

A bidet faucet is installed similarly to a countertop faucet, but it has one additional specific component – the drain kit (also known as click-clack). If you are purchasing, for example, a bidet faucet with drain kit ARKO in chrome or ARKO in satin, the drain kit refers to the mechanism that controls the drain valve in the sink/bidet via a rod system connected to the faucet. For more information on what is included in the package and what needs to be purchased separately, see the article Bidet faucet with drain kit: what is included in the package and what needs to be purchased separately.

When installing a bidet faucet, follow the same steps as for a countertop faucet, with the following additions:

Insert the drain valve into the drain hole of the bidet or sink and secure it with a nut from below
Connect the drain valve to the lever mechanism on the faucet body using the provided rod (adjustable length)
Check the function – the lever on the faucet should open and close the drain smoothly, without jamming

Most common installation errors – from practice

This section is worth reading for everyone who wants to install the faucet themselves. From dozens of resolved complaints and service visits, we have identified several errors that keep repeating themselves over and over again.

Error #1 – Missing or incorrectly used sealing

Teflon tape should NOT be wrapped around the threaded ends of hoses (there is a rubber seal inside there). Tape belongs on external conical or cylindrical threads – that is, on eccentric connectors, corner valves, and other threaded connections without a rubber seal. On the other hand, a flat rubber seal must be present in each hose connector – many people forget it or it falls out during installation and they don't notice. Result: an otherwise tight connection leaks drop by drop.

Error #2 – Over-tightening of threads

The chrome or satin body of the faucet is sensitive to surface damage and internal stress. Broken plastic nuts under the sink and cracked hose connectors are common consequences of over-tightening. The principle is simple: tighten until the connection is watertight – not until the wrench breaks.

Error #3 – Mixing up hot and cold water

Most faucets are designed so that cold water comes from the left and hot from the right. If you reverse this, the faucet will still work, but the cartridge and seals are designed for a specific direction – long-term reversal can shorten the life of the cartridge. In some faucets (see the manual for details), the reversal can even cause the lever to react in the opposite way, which is unintuitive and dangerous – people can get scalded.

Error #4 – Installation without flushing the pipes

Before the first use after installation, always flush the pipes by briefly turning on the water without connecting the faucet (with the hoses connected to the sewer or a bucket). Debris, rust, and sand from the pipes can otherwise get into the new cartridge and damage it – sometimes even on the first opening. This is especially important in old houses or after renovations.

Error #5 – Surface damage during installation

Chrome, satin, or black matte surface finishes are very easily scratched. A wrench or pliers applied directly to the faucet body leaves visible grooves. Always use a rubber hose, a textile strap, or at least a thick cloth as an intermediary. For more information on caring for surfaces, see the article Surface finishes of faucets: chrome, satin, black matte – differences and durability.

Error #6 – Leaving old corner valves in place

When replacing a faucet, people usually only replace the faucet – the corner valves remain. If these valves are more than 15–20 years old, their internal seals are hard and brittle. After a new installation and the first opening, the valve may start leaking, or – in the worst case – it may crack. When replacing any major plumbing fixtures, consider replacing the corner valves as well. The cost is low, and the result is peace of mind for many years.

Special situations and more complex cases from practice

When the wall thread is not sufficient or is damaged

This happens, especially in older panel buildings from the 1980s, when the internal thread in the wall outlet is damaged or too corroded. The eccentric cannot be screwed in deeply enough, or the thread "slips" without resistance. In this case, do not improvise – Teflon tape will not solve the problem. The solution is to replace the wall outlet, which is a job for a plumber. If you want to do it yourself and you know how to solder copper or work with press fittings, it is possible, but requires turning off the entire riser circuit.

When the hole in the sink is too large for the new faucet

Old sinks and basins sometimes have a hole with a diameter of 40 mm or more, while new faucets have a stand with a diameter of only 28–32 mm. In this case, there is no problem – most faucets come with an expanding washer or it is possible to buy a reducing ring. If such a solution is not available and the hole is really non-standard, the only option may be to replace the sink or basin.

Faucet in a large diameter hole turns

If the base of the faucet does not have a rubber anti-slip washer, or if the hole in the sink is slightly larger than the stand, the faucet may rotate after installation when you manipulate the lever. Solution: apply silicone sealing compound (not permanently hardening silicone!) under the base or use a special sealing rubber with a larger diameter. Apply the silicone in a circle and let it harden before turning on the water.

Replacing the cartridge or seal without disassembling the entire faucet

If the faucet leaks or drips from the outlet (spout), the most common cause is a worn-out cartridge – it is not necessary to replace the entire faucet. The cartridge is usually replaced by unscrewing the lever cover and removing the lever. A more detailed procedure is in the article Replacing the seal and cartridge in a faucet: when and how to do it. If the faucet squeaks or has a weak flow, see the article Common problems with water faucets: dripping, weak flow, squeaking.

How to maintain the faucet after installation

Installation is only the beginning. The lifespan of the faucet also depends on regular maintenance. A few rules:

Cleaning: never use abrasive cleaning agents or brushes. For chrome and satin, a damp cloth is enough; for limescale, use a citric acid solution or a specific limescale remover without chloride.
Filter (aerator): unscrew and clean it every 3–6 months. A clogged aerator significantly reduces the flow. Turn it to the left (even if it is marked otherwise), remove it, and rinse it.
Cartridge: with proper handling, it lasts 5–10 years. Forceful turning of the lever, firmly closing it "to the end," and water with a high amount of calcium shorten its lifespan.
Checking connections: once a year, look under the sink and check whether there is any dripping. Micro-leaks can be caught almost immediately and repaired cheaply.

More about cleaning can be found in the article How to maintain and clean faucets without damaging the surface.

Frequently asked questions (FAQ)

Can I replace the faucet myself, or do I need a professional?

Replacing a deck-mounted faucet at a sink or basin is a common task that a technically capable DIYer can handle without a professional license. It only requires the right tools and procedure. More complicated are wall-mounted faucets, where there is a risk of damaging the wall threads, and under-sink faucets, where work is done inside the wall. If you have doubts, it is always better to call a professional – the cost of a service call is lower than the cost of a flooded bathroom or damaged tiling.

How long does it take to replace a faucet?

An experienced plumber can replace a deck-mounted faucet at a sink in 20–30 minutes. A DIYer doing this task for the first time should plan for one to two hours – especially for removing the old faucet, possible complications with old connections, and waiting for the leak test. An experienced technician can replace a wall-mounted bathtub faucet in 30–45 minutes, but adjusting the eccentric to the correct position requires experience.

What to do if the connection still leaks after installation, even though I tightened it?

First, check whether the correct sealing is in place at that location (rubber gasket at the hose connector, or Teflon tape at the threaded connection). If so, slightly tighten it – but not forcefully. If it still leaks, the problem may be a damaged thread (on the connector or on the hose adapter thread). In this case, replace that part – the hose or the angle valve. Never repair a leaking threaded connection with silicone – this is a temporary solution that will worsen later service and does not meet technical standards.

Do I need to turn off the water in the entire house when replacing the faucet?

No, if you have functional angle valves (shut-off valves) under the sink. You only need to close the branch to the specific device. If you do not have angle valves or they do not work, you must close the apartment valve or the riser valve. Always check where exactly the valves are in your apartment and whether they can be turned – old valves may be blocked, and trying to force them open can damage them.

Can I use the old hoses from the original faucet?

Technically yes, but we do not recommend it. Flexible hoses have a recommended lifespan of 5–10 years and their outer casing may not reveal internal damage. Every time you replace the faucet, investing in new hoses is minimal (a few euros) and significantly reduces the risk of bursting with subsequent flooding. Never use hoses with visible cracks, rusty connectors, or damaged braiding.

How do I find out if the new faucet fits my sink or basin?

The key parameters are: diameter of the hole in the sink/basin (standard 35 mm or 38 mm), thickness of the sink surface or ceramic (this determines the length of the stand), and the distance between the inlets (for three-hole faucets, standard 150 mm). Most deck-mounted faucets have an adjustable nut that compensates for different sink thicknesses. If you are unsure, see the article How to choose water faucets for the bathroom and kitchen, where these parameters are explained in detail.

Conclusion

Installing a water faucet is not rocket science, but it requires preparation, the right tools, and discipline in following the procedure. The biggest risks are always in two things: forgetting the sealing and over-tightening the threads. Both of these mistakes are trivially easy to avoid – it is enough to slow down and take a systematic approach. If you follow the procedure described in this article, replacing the faucet should be trouble-free for you. And if you encounter complications that go beyond standard installation – damaged wall threads, a leaking supply system, or non-standard dimensions – do not hesitate to consult a professional. Sometimes the cheapest solution is to call an experienced plumber in time.

Do you have a question about this topic?

Can't decide or are dealing with a specific situation in your home? Write to us – we are happy to help.