By TapWater.uk Research · Updated September 2026 · Independent research
There is no single best water filter for the UK, because there is no single UK tap water. A house in Kent gets very hard water; a flat in Glasgow gets soft. A Victorian terrace may still have a lead supply pipe; a new build will not. PFAS has been found in some catchments and barely monitored in others. The right filter is the one that removes what is actually in your water, and nothing you do not need to pay for. We hold the readings your water company reports for your supply zone, so the fastest route to the answer is your postcode.
Start with what is in your water
Chlorine, hardness, lead, nitrate, PFAS and more, from your supplier's own compliance data. Then come back to the picks.
According to TapWater.uk's 2026 comparison across 2,800 UK postcode districts, the Waterdrop G3P600 is the best water filter for UK homes that want one system to cover PFAS, fluoride, lead and nitrate, with the BRITA Marella XL the best budget jug and the Osmio Zero 2.0 the best reverse osmosis unit that needs no plumbing. Every UK mains supply is chlorinated, which any carbon filter removes. No water filter in this guide reduces water hardness; limescale needs a softener.
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Our picks by need
Find the line that describes your problem. Each pick is the product we rate in that category, with the reason in one sentence and a link to the full guide. Prices are typical and the retailer sets the final figure.
Best overall
Waterdrop G3P600 Reverse Osmosis
Certified to NSF/ANSI 58 and 372 and listed for 12 contaminants, including PFAS, fluoride, lead and nitrate. The widest coverage of anything we compare.
No filter here softens water. Limescale is calcium and magnesium, and carbon, ceramic and tap filters leave them in. You want a water softener for the whole house, or a kettle built for hard water if the kettle is the only problem.
British-made ceramic with NSF/ANSI 42 and 53 certification, listed for bacteria, lead, chlorine and microplastics. The Waterdrop 10UA is the £70 budget route.
The only RO unit we compare that plugs into a socket. Listed for chlorine, lead, bacteria, nitrate, fluoride and limescale, and it dispenses hot as well as cold.
NSF/ANSI 42 and 61 certified with WaterMark approval, and the only whole house unit here listed for bacteria, nitrates and heavy metals as well as chlorine.
Screws onto the tap and comes off when you leave. Listed for chlorine, lead, microplastics and PFAS, though SGS tested rather than NSF certified. The Osmio Zero above is the no-plumbing step up.
One for each budget and each kind of home. The removal lists and certifications below come from the manufacturers' own specifications; the trade-offs are ours.
Best overall: the widest certified removal list we compare
Waterdrop G3P600 Reverse Osmosis
Reverse Osmosis · NSF/ANSI 58, NSF/ANSI 372
Why it fits
Removes 12+ contaminants including PFAS and fluoride
Tankless design saves under-sink space
Smart TDS monitoring panel shows real-time water quality
Trade-offs
Professional installation recommended — plumbing required
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Which type of water filter do you need?
Seven kinds of product get sold as “water filters” in Britain, and one of them is not a filter at all. Price bands and running costs are taken from the products in our catalogue.
Water filter types compared on what they remove, installation, price and running cost
Hardness only: calcium and magnesium, so no more limescale. Not a filter.
Fitted on the incoming main by an installer.
£800–£3,000 installed
Salt top-ups
Running cost is the manufacturer's stated cartridge schedule at typical household use, lowest to highest across the products we list in that category. Whole house and softener prices exclude the plumber.
What UK tap water actually contains
Our picks are grounded in what water companies report across 2,800 postcode districts, not in marketing. These are the five things that decide which filter, if any, is worth your money.
Every UK mains supply is chlorinated to keep it safe in the pipes. It is the swimming-pool taste and smell, and the most common reason anyone buys a filter.
What removes it: Any carbon filter, from a £20 jug up, removes it. A shower filter does the same in the bathroom.
The water company's network is lead-free. What reaches the tap in homes built before 1970 comes from the supply pipe and internal plumbing that was never replaced.
What removes it: A filter certified to NSF/ANSI 53 for lead at the kitchen tap, or replacing the pipe. A whole house filter sits upstream of most of the problem.
The so-called forever chemicals. Detected in some UK supplies and catchments, but monitoring is patchy, so the honest position for most postcodes is uncertainty rather than a clean bill.
What removes it: Reverse osmosis certified to NSF/ANSI 58, or a jug certified to NSF/ANSI 401. Ordinary carbon jugs and whole house filters are not certified for it.
Runs off farmland into rivers and groundwater, so readings are highest in arable areas of eastern and southern England.
What removes it: Reverse osmosis, or the ZeroWater jug. Carbon filters do not remove it.
The top pick in each category, side by side
Listed removals from each maker's own specification. A cross means the maker does not list it, not that it was tested and failed. Bacteria is listed only by the ceramic and RO units.
Anyone noticing dry skin or hair from chlorinated shower water
£85
4.5
£60/yr
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What each one costs over 5 years
Replacement cartridges cost more than most of these filters do. Counting them changes the order. The £70 Waterdrop costs £420 less to own over 5 years than the £40 ZeroWater, despite costing more to buy.
Cartridge costs are the manufacturer’s stated replacement schedule at typical UK household use. Yours will vary with how much water you filter and how hard it is. Prices are approximate — the retailer sets the final price. Across this table the gap between cheapest and dearest to own is £1,050.
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How to read the certifications
A removal claim is only as good as who checked it. These are the marks that appear on the products in this guide, and what each one actually covers.
NSF/ANSI 42
Taste and smell: chlorine and particles. The baseline.
NSF/ANSI 53
Health contaminants such as lead, mercury and cysts.
NSF/ANSI 58
Reverse osmosis systems. Covers the membrane's removal claims.
NSF/ANSI 401
Emerging contaminants including some PFAS and pharmaceuticals.
WRAS approved
Safe to connect to UK mains plumbing. Says nothing about removal.
TUV SUD, SGS tested
Independent lab testing, but not the same as NSF certification of a standard.
Our verdict
Nothing flagged at your postcode and you just want better-tasting water: buy a jug. The BRITA Marella XL is the cheapest good one to live with.
Lead, PFAS or nitrate flagged, or you want one system that covers everything in drinking water: buy the Waterdrop G3P600, or the Osmio Zero 2.0 if you cannot plumb anything in.
Chlorine bothering you at every tap and in the shower: a whole house filter. The Osmio PRO-III Ultimate treats the water; the BWT E1 is the value pick for sediment and chlorine.
Limescale is the complaint: do not buy a filter. Check the hardness at your postcode and read the softener guide.
Before you buy
Check your postcode
See which of the five things above are flagged in your area, and which filter type, if any, we would point you to.
Frequently asked questions
What is the best water filter in the UK?
For most UK homes that want one filter to cover everything in drinking water, the Waterdrop G3P600 reverse osmosis system is the best water filter we have compared. It is certified to NSF/ANSI 58 and 372, lists 12 contaminants including PFAS, fluoride, lead and nitrate, and costs around £550 plus about £144 a year in filters. If you cannot plumb anything in, the Osmio Zero 2.0 is a countertop RO unit that plugs into a socket. If you only want chlorine taste gone, a £25 BRITA Marella XL jug does that for about £52 a year. The right answer depends on what is in your water, which you can check by postcode on this page.
What is the best water filter system for a home?
It depends on how many taps you want treated. For drinking water at the kitchen sink, an under-sink filter such as the Doulton HIP Ultracarb (NSF/ANSI 42 and 53, around £120) or a reverse osmosis system such as the Waterdrop G3P600 gives the best result per litre. For every tap, shower and appliance, a whole house filter fitted on the incoming main is the route: the Osmio PRO-III Ultimate (around £499) is the one we rate, with the BWT E1 (around £250) as the value pick for sediment. No whole house filter in our catalogue softens water, so a hard water home usually adds a softener alongside it.
Do I need a water filter in the UK?
Not for safety. UK mains water meets the Drinking Water Inspectorate's standards at the tap, so nobody on a public supply needs a filter to make it safe to drink. People buy one for taste and smell (chlorine is in every mains supply), for lead from old pipes in pre-1970 homes, for PFAS where it has been detected locally, or for peace of mind. Check your postcode first: if nothing is flagged in your area, a filter is optional and a cheap jug covers taste.
What is the difference between a water filter and a water purifier?
In UK shops the words are used loosely and often mean the same product. Strictly, a filter removes some contaminants by passing water through a material such as carbon, ceramic or a membrane, while a purifier is a system that removes or kills a very wide range including bacteria and viruses. In practice, reverse osmosis systems and ceramic filters such as the Doulton HIP Ultracarb (listed for bacteria) do what most people mean by purifier, and a carbon jug is a filter for taste and a few metals. Ignore the label and read the removal list and certifications instead.
Which water filter removes the most contaminants?
Reverse osmosis. Of everything in our catalogue, the Waterdrop G3P600 lists the most contaminants at 12, including PFAS, fluoride, lead, arsenic, nitrate, chlorine, trihalomethanes, mercury, cadmium, chromium, copper and nickel, and it is certified to NSF/ANSI 58. The Osmio Fusion and Zero units list a similar spread including bacteria and limescale, but without a stated NSF or WRAS certification. Among jugs, the ZeroWater 12-Cup lists eight contaminants including PFAS and fluoride, certified to NSF/ANSI 53 and 401.
Are water filters worth it in the UK?
Worth it for taste, yes, at almost any budget: a £20 to £25 jug removes chlorine for £36 to £52 a year in cartridges. Worth it for health depends on your water. If your postcode shows lead, PFAS or nitrate flagged, a certified under-sink or reverse osmosis system is a sensible purchase. If your problem is limescale, no filter is worth it, because filters do not soften water; you want a water softener or a kettle designed for hard water. Count the running cost as well as the price: over five years a £40 jug can cost more to own than a £70 under-sink filter.
What is the best water filter for hard water in the UK?
A filter is the wrong product for hard water. Hardness is dissolved calcium and magnesium, and carbon, ceramic and tap filters leave it in the water, so limescale carries on forming. To stop scale across the whole house you need an ion exchange water softener, typically £800 to £3,000 installed. For a single kettle, the Russell Hobbs BRITA Purity kettle reduces temporary hardness before the water boils. Reverse osmosis units do list limescale removal, but only for the drinking tap they feed. Our water softener guide and kettle guide cover both routes.
How much does a home water filter system cost in the UK?
From our catalogue: water filter jugs cost £20 to £40 with cartridges of £36 to £120 a year; tap-mounted filters £30 to £60; under-sink filters £70 to £120 with £30 to £80 a year in cartridges; reverse osmosis systems £450 to £650 for the unit, with the Waterdrop G3P600 at around £550, and £107 to £144 a year in filters; whole house filters £250 to £499 plus fitting, with running costs from nothing (the BWT E1 backwashes itself) to around £188 a year; shower filters £25 to £85. A water softener is a different product at £800 to £3,000 installed.
