Proper water, straight from the tap.
Hard water is a British problem: furred-up kettles, cloudy glasses and tea that never quite tastes right. Clarisink fits a filter under your sink that deals with limescale, chlorine and contaminants — quietly, out of sight, no plastic bottles in the recycling.
Free UK delivery · 2-year warranty · 30-day returns · VAT included
Which filter does your kitchen actually need?
There is no single best filter — it depends on what is wrong with your water. Tell us what you notice at the tap and we will point you at the right technology, not the priciest box.
Not sure which applies? Our UK hard water guide shows typical hardness for your region in under a minute.
- 01
Kettle furs up in weeks
Reverse osmosis or limescale conditioning
Scale means dissolved calcium and magnesium. Only RO removes them outright; the Limescale Defender stops them bonding to surfaces.
See RO systems - 02
Water tastes of chlorine
Carbon block filtration
Chlorine and its by-products are what most people are tasting. A 0.5-micron carbon block removes them without stripping natural minerals.
See carbon filters - 03
No spare hole in the worktop
A 3-way or boiling filter tap
One tap for hot, cold and filtered water. Keeps the worktop clear and means no second spout drilled into granite.
See filter taps
The Clarisink range
Under-sink filtration systems, filter taps and genuine replacement cartridges — priced with VAT included and delivered free across the UK.
Reverse OsmosisClarisink RO-400 Reverse Osmosis System
£199.00
VAT included
Reverse OsmosisClarisink RO-500 Tankless Reverse Osmosis System
£249.00
VAT included
Reverse OsmosisClarisink RO-300 Compact Reverse Osmosis System
£179.00
VAT included
Limescale FilterClarisink Limescale Defender Under-Sink Filter
£149.00
VAT included
Limescale FilterClarisink Hard Water Carbon Block Filter
£129.00
VAT included
Filter TapClarisink 3-Way Filter Tap — Chrome
£169.00
VAT included
Filter TapClarisink Boiling Water Filter Tap
£239.00
VAT included
CartridgeClarisink RO-400 Replacement Membrane Cartridge
£39.00
VAT included
CartridgeClarisink Carbon Block Replacement Cartridge
£24.00
VAT included
CartridgeClarisink Limescale Replacement Cartridge
£29.00
VAT included
Around 60% of UK homes have hard water
Water hardness in the UK is a story of geology. Rain falling on the chalk and limestone of the South East and East Anglia picks up calcium and magnesium on its way down; the granite of Scotland, Cornwall and Snowdonia gives it almost nothing. That is why a kettle in Chelmsford furs up in a month and one in Glasgow lasts for years.
Hard water is not a health risk — the minerals are harmless, and some research links them to modest benefits. It is a nuisance problem: scale in the kettle and shower, spotting on glassware, more detergent, shorter appliance life, and a chalky edge to tea and coffee.
Read the full UK hard water guide| Region | Hardness | What that means |
|---|---|---|
| London & South East | Very hard | 270–400 ppm — RO strongly recommended |
| East Anglia | Very hard | Among the hardest water in Britain |
| Midlands | Hard | Mixed supply, scale on kettles is common |
| Yorkshire & Humber | Moderate | Varies sharply by town |
| North West & Wales | Soft | Carbon filtration for taste is usually enough |
| Scotland & Cornwall | Soft | Low mineral content, chlorine is the main complaint |
What our customers say
Every review below was written by someone who bought from Clarisink. We moderate for spam and abuse — we never write, buy or edit reviews.
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Clarisink is a new shop, and we've taken a deliberate decision not to fill this page with invented testimonials. When customers start writing in, their words appear here exactly as they sent them — good and bad. You can leave a review on any product page.
Guides worth reading before you buy
Plain-English explanations of water hardness, filtration technology and installation — written to help you choose, not to sell you the dearest system.
Best Under-Sink Filter UK
How to pick the right filter for your symptoms, cupboard and budget.
Read guideUK Hard Water Areas
Region-by-region hardness, in ppm, and the filter that suits each.
Read guideHow to Fit a Filter
A realistic DIY walkthrough, including the fiddly bits.
Read guideChanging Cartridges
When to replace, what happens if you don't, and typical costs.
Read guideCommon questions
Still unsure? Email support@clarisink.com and a person will reply — usually the same working day.