The shower enclosure is where hard water shows up first and worst. In the Copenhagen area the water is naturally hard — HOFOR puts much of the capital above 20 degrees dH — so every shower leaves dissolved calcium behind on the glass as the water dries. Left alone, that thin haze hardens into a crust that ordinary bathroom spray will not touch.
The good news: the enclosure is one of the few places where the strong stuff is allowed. The trick is knowing which parts of it tolerate acid, which do not, and how to make the product do the work instead of your arm.
First: what is your enclosure actually made of?
"Clean the shower" sounds like one job. It is four or five different ones, and the product that saves you an hour on one part ruins another.
- Tempered glass and ceramic or porcelain tiles tolerate an acidic descaler well.
- Cement grout is alkaline and slowly degrades under repeated acid, which is how joints end up crumbly and discoloured.
- An acrylic tray or bath tolerates the product but not the pad: abrasives leave a permanent milky patch.
- Chrome taps and shower heads tolerate short contact only, and never abrasives.
- Natural stone — marble, travertine, limestone, terrazzo — tolerates no acid at all. It is the same chemistry as the limescale, so the acid dissolves the stone. If any part of your bathroom is stone, read our guide to limescale on marble, brass and glass before you open a bottle.
The glass: contact time, then a blade
This is the part people fight with a sponge for twenty minutes and lose. Limescale is a mineral deposit; it does not wipe off, it has to be dissolved.
- Wet the glass first. A dry surface makes the product run straight off.
- Apply an acidic descaler and leave it. Give it the contact time on the label. On heavy scale, lay kitchen paper against the glass and spray through it — the paper holds the product in place instead of letting it slide into the tray.
- Work it with something soft, not something rough. A microfibre cloth or a non-scratch pad. Scouring pads and abrasive powder leave micro-scratches that catch the light forever, and once glass is scratched it holds scale worse, not better.
- For the last hazy film, use a glass scraper. A flat blade held almost parallel to the glass, on a wet surface, lifts the remaining crust safely. Held at an angle it gouges. This is the single tool that most changes the result.
- Rinse and dry. Any residue left behind dries into a new film.
If your glass has a factory water-repellent coating, skip the blade and the acid entirely — use a mild neutral cleaner, because acid strips the coating and the glass then scales up faster than before.
Tiles and grout: acid on the tile, not in the joint
Descaler on the tile face is fine. What damages the bathroom is descaler left to dry in the grout lines, which happens by default if you spray a whole wall and walk away. Work in sections, keep the product moving, and rinse the wall thoroughly before it can dry.
Discoloured grout that stays grey after descaling is usually not scale — it is soap residue or mould, and it needs a different product. Which brings us to the one rule that matters more than any of this.
The mistake that sends people to hospital
Mould in the silicone joints is treated with a chlorine-based product. Limescale is treated with an acid. Never use them together, and never one straight after the other in a closed bathroom. Mixed, they release chlorine gas. This happens in real flats every year, to people who were simply trying to do both jobs in one afternoon.
Do one, rinse the surface completely, ventilate the room, and only then start the other. Window open, gloves on, both times.
The shower head
Blocked or spraying sideways almost always means scale in the nozzles, not a broken head. Unscrew it if you can and stand it in a descaling solution; if it will not come off, a bag of solution tied around it does the same thing. Afterwards, rub the rubber nozzles with a thumb — the softened deposits pop straight out. Metal picks and needles scratch the seat and make it worse.
The drain, while you are there
Lift the cover, pull the hair, and clean underneath. This is on essentially every landlord's handover list and it is the item most often forgotten, because the cover looks fine from above.
Keeping it from coming back
With water this hard, the only thing that actually works is not letting the water dry in place. A squeegee pulled down the glass after each shower takes thirty seconds and removes the calcium before it can bond. Dry the taps. Leave the door open and ventilate so the room dries fast. Fresh scale wipes off with a cloth; three-month-old scale is a project.
When this suddenly gets expensive
Bathroom limescale is one of the most common deductions from a deposit at a Danish move-out inspection — it is visible, it is easy to point at, and it is written into most handover lists. Our guide on doing the move-out cleaning yourself goes through what actually gets checked, room by room, and which product belongs on which surface.
If you want the version specific to your own home, our Move-Out Package (DKK 499) reads your lease and your landlord's handover list and turns them into the list they will actually check, with the method for each item and a shopping list of the product types your bathroom needs. Send a photo of what you are stuck on and a person answers the same day. Book a move-out cleaning with us and the same package is included free.
Quick answers
Does vinegar work on shower glass?
Yes, on glass and ceramic tile it works, just more slowly than a dedicated descaler. Keep it away from natural stone, from grout lines, and from anything with a water-repellent coating.
Is there a descaler without acid?
There are low-acid and "acid-free" products, and they are gentler on grout and finishes, but they are correspondingly slower and struggle with thick deposits. On stone they are the only option; on glass, an acid with proper contact time is quicker.
My glass stays cloudy even after descaling. Why?
Usually one of two things: scale that has been left long enough to etch the glass surface, or micro-scratches from an abrasive pad used earlier. Etching cannot be cleaned off — the glass has changed. Repeated gentle treatments will sometimes improve it; if not, it is a replacement, which is worth knowing before you attack it harder.
Home Clean Service ApS · CVR 46336720 · Copenhagen · +45 91 62 83 99 · support@homecleancph.com. General cleaning information based on professional experience; always follow the product label and test on a small hidden area first.
