How do I get rid of the hard limescale ring in the toilet?

Everyone who has this problem has already tried cleaning it. The reason it does not work is not the product: it is that the deposit is under water, so anything poured in is diluted to nothing before it can act. Get the water away from it and ordinary descaler works exactly as it should. Everything below follows from that single fact.

Safety

What you'll need

• A toilet descaler, or citric acid, or a limescale remover rated for ceramics
• Gloves and eye protection
• A jug or a small cup for bailing
• A toilet pumice stick, for heavy deposits
• A stiff nylon brush
• A washing-up bowl

Step by step

1. Turn off the supply and empty the cistern.Close the isolating valve on the toilet supply, then flush and hold the flush open. Empty the cistern completely so nobody refills the pan while you are working.
2. Get the water out of the pan.Bail as much as you can out with a jug into a bucket. Then push the remainder round the trap with a toilet brush or a plunger — a few sharp pushes sends the water over the weir and leaves the bowl and the visible trap almost dry. Mop the last of it with kitchen roll.
3. Apply the descaler directly to the dry deposit.With no water diluting it, the product sits on the scale and works. Apply generously to the ring and anywhere else the scale is visible. A gel clings better than a liquid on a curved surface.
4. Leave it as long as the product allows, then longer if it is safe to.Read the label. Most toilet descalers want somewhere between fifteen minutes and a couple of hours. Time is doing the work here, not effort.
5. Work it with a nylon brush and re-apply.After the dwell, brush firmly. You will usually take a layer off rather than the whole ring. Re-apply and leave it again. Two or three cycles removes deposits that no single application would touch — and each cycle is five minutes of your attention.
6. Use a pumice stick on what is left.A toilet pumice stick, wetted, is softer than vitreous china and harder than limescale, so it abrades the deposit without scratching the glaze. Keep both the stick and the surface wet throughout, work gently, and stop the moment you feel it dragging on bare glaze. Never use a dry pumice, and never use a scouring pad, sandpaper or a scraper.
7. Deal with the underside of the rim while you are there.The same deposit is under the rim, blocking the flush jets and weakening the flush. Apply the same descaler up under the rim with the water down and clear the jets with a wire or a cable tie.
8. Restore the water and flush thoroughly.Open the isolating valve, let the cistern fill, and flush several times to dilute and clear all the product before the toilet goes back into use.
9. Stop it coming back with a habit, not a product.In a hard water area the ring reforms. Brushing round the water line as part of a weekly clean, before a deposit is established, keeps it away permanently. Once it has hardened it is far harder to remove than to prevent.

Common mistakes

• Pouring descaler into a full pan — It is diluted to a fraction of its strength before it reaches the scale. This is why cleaning the ring never works and it is the whole problem.
• Mixing a descaler with bleach — Acid and hypochlorite release chlorine gas, and you are leaning over a bowl. Use one product, flush thoroughly, and only then use another.
• Attacking it with a scourer, a scraper or wet-and-dry paper — Vitreous china's glaze is what makes a toilet cleanable. Scratch it and the bowl stains and scales faster forever after.
• Using a pumice dry — A dry pumice scratches. Both the stone and the surface must stay wet.

Questions people ask