Cleaning and descaling of the water heater - how to extend its lifespan

We are still preparing products.

But you can look at other categories.

Cleaning and descaling a tap – how to extend its lifespan

A tap is one of those devices we think about the least – until it starts causing trouble. It drips, water flows weakly, the lever moves stiffly, or the aerator whirs. Most of these problems have the same cause: limescale and impurities that gradually settle inside the tap, on the aerator screen, on the surface of the fixture, and in the cartridge. In areas with hard water – and this is most of Slovakia – these problems can start to bother you after two to three years. The good news is that regular cleaning and descaling can extend the life of the tap several times over, and you can do it yourself without calling a plumber.

In this article, we will go through the entire process from A to Z: how to recognize that the tap needs cleaning, what tools and materials to use, how to proceed step by step for different types of taps and their components, and what to do preventively to minimize the need for descaling. If you are also interested in finding out which tap is suitable for your bathroom or kitchen, we recommend reading the article How to choose Stern taps – what to focus on before buying.

Why water damages taps and what water hardness is problematic

Tap water contains dissolved minerals – mainly calcium and magnesium. Their content is measured in German degrees of hardness (°dH) or millimoles per liter. In Slovakia, water hardness ranges from soft (under 7 °dH) in mountainous areas to very hard (over 21 °dH) in limestone areas, for example, parts of southern Slovakia or the Záhorie region. In most cities, water is moderately hard to hard, i.e., in the range of 12–21 °dH.

The problem arises when water is heated or evaporates on the surface of the fixture. Dissolved calcium bicarbonate decomposes into insoluble calcium carbonate – limescale – at temperatures above 60 °C. It settles everywhere where water flows, evaporates, or comes into contact with warm surfaces. In a tap, this means: aerator, seals, cartridge, internal channels, and the surface of the fixture. The harder the water, the faster the limescale accumulates. At a hardness level above 20 °dH, the aerator can be significantly clogged within 12–18 months, and the cartridge can be damaged within 3–5 years.

How to recognize that the tap needs cleaning or descaling

An experienced plumber can usually tell the condition of a tap at a glance, but even a layperson can notice several clear warning signs:

Weak water pressure from the outlet – with normal water pressure in the water supply network (typically 2–5 bar), only a thin stream flows from the tap. The aerator is often the first suspect.
Uneven or splashing water stream – water flows sideways instead of straight down. The aerator screen is partially clogged.
Stiff or squeaky lever – limescale has settled around the cartridge or deposits have entered the sliding mechanism.
Dripping after closing – can be a combination of worn seals and limescale on the cartridge seat.
White, gray, or yellowish coating on the surface – typical limescale, or rust from pipe systems.
Unpleasant odor or change in water taste – accumulated deposits and biofilm in the aerator (especially after prolonged inactivity of the tap).

If you are also dealing with dripping or other malfunctions, you can find more information in the article Dripping or leaking Stern tap – causes and repair, where mechanical causes of faults are discussed in detail.

What you will need – tools and cleaning agents

Before starting the cleaning process, prepare everything you will need. Unnecessary interruptions during the process (when the tap is disassembled and the water is turned off) are a source of stress and errors.

Tools

Flathead screwdriver and crosshead screwdriver (size PH2)
Adjustable wrench or pliers
Special aerator key (some aerators are hidden under a cap and must be unscrewed with a special key – included with the tap purchase)
Plastic container or deep bowl (for soaking parts)
Old toothbrush or small brush with stiff bristles
Soft microfiber cloth (for polishing the surface)
Hose or bag for securing the solution during soaking of the installed aerator

Cleaning agents

Vinegar (white, 8–10 %, or diluted to 3–5 %) – a classic household remedy, safe for most surfaces and materials. Acetic acid dissolves calcium carbonate.
Citric acid (5–10 % solution in warm water) – a gentler but effective agent. Suitable for chrome surfaces. Available in powder form in stores.
Commercial descalers – products such as Cillit Bang, Durgol, Viakal, and similar. Usually contain sulfamic acid or lactic acid. The advantage is the speed of action and often a gel consistency that stays on the surface. Disadvantage: more expensive and compatibility with the tap material must be checked.
Baking soda – a weak base, does not descale, but is suitable for mechanical cleaning and neutralizing acids after descaling.
Window cleaner or isopropyl alcohol – for final polishing of the chrome surface.

What NOT TO USE: Abrasive powders (Vim and similar), steel wool, hydrochloric acid (muriatic acid) on chrome surfaces – they will damage the faucet's surface coating. On nickel or gold surfaces, do not use undiluted vinegar for more than 5 minutes.

Cleaning the aerator – the first and most frequent step

The aerator is a small screw-on part at the end of the faucet outlet. It contains a mesh (or multiple meshes) that disperses the water flow and mixes air into it, creating a softer, more satisfying stream. This mesh captures all impurities and limescale from the tap water. It is the first component that needs cleaning and the one where the effect is immediately visible.

Steps for cleaning the aerator

Unscrew the aerator – usually by hand (M22 or M24 thread is standard, some aerators have a smaller M18.5 thread). If it is stuck due to limescale, soak a cloth in warm vinegar and place it over the outlet for 15–30 minutes, then try again. Never use pliers directly on the chrome surface – place a piece of leather or rubber underneath.
Disassemble it into parts – inside you will usually find 2–4 parts: a gasket, a mesh (or meshes), and a flow-directing insert. Pay attention to the order and orientation of the parts – take a photo before disassembling.
Soak the parts in a solution – pour diluted vinegar (1:1 with water) or a 5–10% solution of citric acid into a container. Place the parts in and let them soak for 30–60 minutes. For heavy deposits, up to 2–3 hours or overnight.
Clean mechanically – an old toothbrush will remove remaining limescale from the mesh and insert. With very fine meshes, be careful not to damage them.
Rinse and reassemble – thoroughly rinse each part with clean water (possibly neutralize with baking soda), reassemble in the correct order, and screw it back on. Tighten only by hand – it is sufficient for a chrome surface, no tools are needed.

Practical experience: In practice, we often encounter customers who, after years, find out that they cannot unscrew the aerator at all, as it is literally "welded" by limescale. In such cases, long soaking (even several hours) with a hot vinegar solution helps, or connecting a silicone hose to hot water. If that still doesn't work, replace the aerator – it is not an expensive item (1–5 €) and is available according to the thread diameter.

Descaling the faucet surface – chrome, matte, and special finishes

Limescale on the external surface of the faucet is primarily an aesthetic issue, but over time it can damage the surface coating, leading to stains, corrosion spots, and peeling. Different surface treatments require different approaches.

Chrome finish

Chrome is resistant to weaker acids, but prolonged contact with acids (even vinegar) can damage the shine over years. Recommended: diluted vinegar (1:2 to 1:3 with water) or citric acid (5%) on a cloth. Let it sit for 5–10 minutes, then wipe and rinse. Finish by polishing with a dry microfiber cloth.

Matte black or dark surfaces (PVD coating)

PVD (Physical Vapour Deposition) coating is very hard but sensitive to acids. Never use vinegar or citric acid on these surfaces. Only neutral detergents based on surfactants or special cleaners recommended by the manufacturer are suitable. In this case, the best approach for limescale is mechanical – moisten a soft cloth with warm water and gently rub the deposits away with circular motions.

Brass, gold, or bronze finishes

These surfaces are more sensitive. Do not use undiluted vinegar directly. A low concentration (2–3%) of citric acid is acceptable, but limit the contact time to 2–3 minutes. After treatment, rinse thoroughly and dry.

In general, the rule we emphasize to everyone applies: read the manufacturer's instructions for your faucet. Faucets Stern are produced in various surface finishes, and each requires appropriate care.

Cleaning and descaling the cartridge

The cartridge is the heart of a modern single-lever faucet. It is a ceramic or plastic valve component that controls the flow and temperature of water. Limescale enters the cartridge through the water and gradually reduces its mobility – the lever becomes stiff, the faucet drips or cannot be regulated properly. More on step-by-step cartridge replacement can be found in the article Replacing seals and cartridges in Stern faucet – procedure and spare parts.

Cleaning the cartridge without replacement is possible, but only to a certain extent. Procedure:

Close the water supply – the main shut-off valve or the shut-off valve under the faucet (angle valve).
Disassemble the cartridge – remove the lever cap, unscrew the mounting nut, and remove the cartridge (the procedure varies by faucet type – see the section on assembly or the article Installation of a water faucet Stern step by step – DIY or with a plumber).
Clean the outer surface of the cartridge – soak in a 5% citric acid solution for 20–30 minutes. Gently clean the inlet and outlet holes with a brush.
Ceramic discs – ceramic is hard and resistant to acids. It can be cleaned with the same solution. WARNING: ceramic discs must not be scratched – never clean them with abrasive materials.
Reassemble and test – reinstall the cartridge, check the orientation (most cartridges have notches or arrows), tighten, open the water and test the function.

In practice: if the cartridge is still stiff or dripping after cleaning, cleaning is not enough and the cartridge is worn out. Ceramic discs have a limited lifespan, and in cheaper faucets, this is 3–5 years with daily use. High-quality cartridges (e.g., from the Spanish manufacturer Sedal or Kerox) last significantly longer. When choosing a new faucet, it is worth asking about the type and brand of the cartridge – more in the article Certificates and quality of Stern faucets – what standards and warranties mean for you.

Cleaning the inside of the faucet body and supply hoses

The internal channels of the faucet body slowly clog up, but with very hard water or an older installation, larger deposits can form. The problem also includes the supply hoses (flexible connections under the faucet), where the mesh filter is directly in the coupling.

Filter in the hose supply head

Almost every hose (flexible connection) has a small mesh on both ends that catches coarse impurities. Unscrew the hose, remove the mesh with pliers, and clean it in the same way as an aerator. This mesh is often forgotten, but when clogged, the problem looks the same as with a clogged aerator – low pressure.

Internal channels of the faucet body

If the pressure remains low after cleaning the aerator and mesh, the problem may be inside the faucet body. In such a case, close the water, disassemble the cartridge, and let a citric acid solution flow through the channels – fill the faucet body with the solution (e.g., using a damp spray bottle) and let it work for 1–2 hours. Then rinse with water. It is a laborious procedure, but in practice, it is appreciated especially by owners of older houses with pipes, where rust or sand occasionally loosens from the pipes.

Cleaning of shower hoses, handheld showers and thermostats

If your faucet also has a handheld shower or is a combination of a faucet and a thermostatic mixer, you should also consider these parts. The handheld shower has nozzles through which water flows – these nozzles clog up with limescale very quickly, especially with hard water.

Handheld shower

Most modern handheld showers have nozzles made of soft silicone or rubber, which is practical – it is enough to press each nozzle with a finger and the scale falls out. Otherwise, procedure: unscrew the shower head (or soak it completely), place it in a vinegar or citric acid solution for an hour, clean with a brush, and rinse.

Shower hose

The hose itself does not retain much scale, but the inner layer can be covered with biofilm (especially with warm water). Clean the inside of the hose with a 5% citric acid solution – close one end (with a finger or a plug), fill with the solution, close the other end and let it work for 30 minutes. Rinsing with clean water is mandatory before reuse.

Thermostatic Faucet

Thermostatic faucets have a memory shape thermostat inside (bimetal or wax element). Limescale can prevent proper operation and the water temperature will not match the set value. Cleaning a thermostatic valve is more complex and we recommend entrusting it to a professional or following the manufacturer's instructions. Clean the outer surface in the same way as a conventional faucet.

Prevention – How to Slow Down Limescale Formation

Cleaning is important, but even more important is preventing problems in advance. There are several proven approaches:

Water Softener (Ion Exchange)

Installation of an ion exchange water softener for the whole house is the most effective solution. It reduces water hardness to a value of around 7–8 °dH, significantly slowing down limescale formation. The cost of a complete installation ranges from €600 to €1,500 depending on capacity and manufacturer. For households with hard water (over 20 °dH), the investment pays off through the extended lifespan of the water heater, washing machine, dishwasher, and faucets.

Magnetic or Electrolytic Water Conditioner

These devices are mounted on the supply pipe and physically change the structure of calcium crystals – limescale still forms, but it has different properties (less adherent, easier to remove). Their actual effectiveness is a subject of debate, but many users report positive experiences. The price is low (from €20 to €150).

Wiping the surface regularly after each use

The simplest form of prevention: wipe the faucet surface with a soft cloth or rubber spatula after each use. This prevents droplets from evaporating and leaving limescale stains. In bathrooms with high humidity, this makes the difference between a nice and an ugly faucet surface within one year.

Surface protection products

There are special sprays and products (e.g. based on wax or silicone) that create a hydrophobic film on the faucet surface. Water runs off, does not settle, and the surface is much easier to clean. Apply 1–2 times a year on a clean, dry surface.

Regular inspection and service intervals

We recommend cleaning the aerator at least once a year and inspecting the cartridge and seals every 2–3 years. In areas with hardness above 20 °dH, reduce the aerator interval to every 6 months.

What to do when cleaning is not enough

Sometimes the damage is so extensive that cleaning won't solve the problem. The cartridge is eroded, the seals are hard and cracked, and the inside of the faucet is rusty. In such a case, it is more sensible to invest in a new faucet rather than chasing expensive repairs for an old one. Especially if the faucet is older than 10–15 years, replacing it with a new Stern water faucet is more economically and technically advantageous.

A new faucet brings several benefits at once: a new cartridge with full warranty, modern ceramic technology, lower water consumption (aerator with perlizator), and possibly also energy savings (thermostatic or eco-restriction mode).

If you are considering choosing a new model, read the article Basin vs. Shower vs. Bathtub Faucets Stern – Differences and Use and also Single Lever vs. Two-Handle Faucet – Which is Suitable for Your Bathroom.

Frequency of cleaning – practical overview by water hardness

Water hardness	Degree (°dH)	Aerator	Cartridge / Seals	Faucet surface
Soft	under 7 °dH	1× per year	every 5–7 years	as needed
Medium hardness	7–14 °dH	2× per year	every 3–5 years	1× per month
Hard	14–21 °dH	3–4× per year	every 2–3 years	2× per month
Very hard	over 21 °dH	every 2 months	every 1–2 years	weekly

Safety when working with acids and cleaning agents

Although vinegar and citric acid are common food acids, they can irritate the skin with prolonged contact. Commercial descaling agents are more aggressive and should be handled with care:

Always read the label and follow the recommended exposure times
Before applying to the faucet, test the product on an inconspicuous area
When working with strong commercial descalers, wear rubber gloves
Work in a well-ventilated area
After descaling, always thoroughly rinse all parts with clean water before using the faucet for drinking water or bathing
Never leave leftover solution in sealed containers – pressure from CO₂ (from the reaction of acid with carbonate) can unexpectedly open the container

Most common mistakes when cleaning a faucet

From practice, we know that people make several recurring mistakes when cleaning a faucet:

Cleaning with abrasive agents – micro-scratches on the chrome surface are permanent and limescale and dirt accumulate even worse in them.
Forgetting about the mesh in the hose connector – you clean the aerator, the pressure doesn't improve, and you wonder what's wrong.
Using an overly aggressive cleaning agent on the wrong surface – a gold or bronze surface treated with an industrial descaler for 30 minutes = permanent damage.
Leaving the aerator loose after installation – it leaks and the wet surface under the faucet becomes a source of further limescale and biofilm.
Improperly reassembling the cartridge after cleaning – incorrect orientation of the cartridge causes cold and hot water to be swapped.
Using metal tools directly on the polished surface – always use a rubber or leather pad.

Frequently asked questions (FAQ)

Can I leave the aerator soaked in vinegar overnight without unscrewing it?

Yes, this is a common method: fill a plastic bag with a vinegar solution, secure it with a rubber band around the outlet so that the aerator is submerged, and leave it overnight. In the morning, simply unscrew it and clean it with a brush. This method works well for moderate buildup. For very heavy buildup, we recommend unscrewing the aerator and soaking it separately.

How can I find out the water hardness in my area?

Water hardness is published by your local water utility – usually on their website or upon request. Approximate values can also be found on the water hardness map of Slovakia. Alternatively, you can purchase water hardness test strips (available in aquarium shops or online for a few euros), which give results in a minute.

What to do if the aerator cannot be unscrewed even after long soaking?

Try using a special aerator key (supplied with the faucet or available separately). If it still doesn't work, gently tap the outlet with a wooden stick or a rubber mallet – the vibration may break up limescale deposits. If that also doesn't help, the aerator needs to be replaced – a new one is very affordable and the Stern product is available as a standard spare part. Alternatively, consult the article Common Questions about Stern Faucets – Water Pressure, Compatibility, Warranty and Service.

Can I clean the faucet with a commercial limescale remover from the store?

It depends on the faucet surface. Yes, for standard chrome faucets, but follow the recommended contact time (usually 5–10 minutes, not hours). Do not use commercial descaling agents on matte, black, gold, or bronze surfaces without explicit permission from the manufacturer – they could permanently damage the surface coating. In case of doubt, use diluted citric acid, which is gentler.

How long does a full faucet cleaning including the aerator and cartridge take?

If you're experienced and have the tools ready, disassembly, cleaning, and reassembly alone take 30–60 minutes. Add the soaking time (30 minutes to several hours) depending on the level of buildup. Overall, plan for half a day if you're doing a full service including the spout, aerator, and cartridge.

Is there any way to completely prevent limescale?

To completely prevent limescale, you would need distilled or demineralized water, which is unrealistic for home use and also unhealthy (demineralized water is not potable). The closest solution is an ion exchange water softener, which reduces hardness to a minimal level. Combined with regular wiping of the surface and occasional aerator cleaning, the limescale issue can be reduced to a minor nuisance.

Conclusion – the lifespan of the faucet depends on you

A water faucet is not a consumable item that is simply thrown away and replaced. A well-maintained quality faucet can last 15–20 or even more years without significant problems. The key is regular care: clean the aerator according to the water hardness, wipe the surface after each use, and check the condition of the seals and cartridge at least once every few years.

Cleaning and descaling are not difficult – any handy DIYer can do it without special tools and for just a few euros in supplies. The results are immediately visible: better water pressure, smoother regulation, and a nicer faucet appearance. And your faucet will reward you with more years of trouble-free operation.

If you're also considering new accessories or thinking about replacing old faucets with more modern models, take a look at the range of Stern water faucets – you'll find models for the bathroom, kitchen, and shower in various surface finishes and price ranges.

Do you have a question about this topic?

Having trouble deciding or dealing with a specific situation in your home? Write to us – we're happy to help.