Key takeaways
- The Drinking Water Inspectorate reported that 99.97% of 3.5 million regulatory samples from public supplies in England met the standards in 2025. Its advice to consumers is that no treatment at home is needed as a health protection measure.
- Two BRITA cartridges sit in the Amazon UK Home & Kitchen top 20 today, at number 2 and number 15. They fit the same jugs and do different jobs, and which one suits you is decided by how hard your tap water is.
- At today’s prices a cartridge works out between 2.0p and 2.8p per litre filtered. Thames Water charges £2.7346 per cubic metre for clean water, which is 0.27p a litre, so the cartridge costs seven to ten times as much as the water going through it.
- The Inspectorate says jug filters containing ion exchange beads change only the temporary hardness of water. They will not soften your supply, and leaving a cartridge in past its change date lets deposits build up and bacteria breed.
Filter jugs are quietly one of the steadiest sellers in the British kitchen, and the charts show it in an unusual way. The jugs themselves are not what climbs the Amazon UK Home & Kitchen best sellers. The refill cartridges are. On the chart this morning the BRITA MAXTRA PRO Pure Performance six pack sits at number 2, and the MAXTRA PRO Limescale Expert six pack sits at number 15. Same fitting, same jug, two different products, both selling hard on the same day.
That tells you something about how people buy these. The jug is a one off purchase you barely think about. The cartridge is the thing you keep paying for, and it is where the choice that matters actually gets made. So before the jugs, what the people who regulate your tap water have to say about all of this.
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Prices and specs last checked 4 October 2026 · next check 29 November 2026 · how we picked
What the regulator says a filter jug is for
Drinking water in England and Wales is regulated by the Drinking Water Inspectorate, which publishes a Chief Inspector’s report every year. The 2025 report, published in July 2026, says public supplies in England met the regulatory standards in 99.97% of tests across more than 3.5 million samples. Of the 982 failures, 447 were attributed to the consumer’s own distribution system, which means the pipes and fittings inside the building rather than the water the company put into the main.
The Inspectorate’s consumer guidance on domestic filters is blunter than anything you will read on a product page. It says tap water is safe to drink and there is no need to install additional treatment within the home as a health protection measure. On pesticides it says home water treatment is not required, because companies already treat to below the regulatory standards. It names taste and odour as the most common reason people actually buy a filter, and it points out that a covered glass jug of tap water in the fridge is a cheaper way to get the same improvement.
Where the Inspectorate does raise a risk, it is about the cartridge rather than the water. Its guidance says that failing to follow the manufacturer’s advice on maintenance and cartridge change frequency will cause a build up of deposits, create a breeding ground for bacteria, and cause removed material to leach back into the drinking water. The jug you buy matters far less than whether you keep to the change schedule after you buy it.
The hardness split behind the two best selling cartridges
Water hardness comes from dissolved calcium and magnesium picked up from local geology, so it varies enormously across the country. The Inspectorate publishes the bands, measured in milligrams per litre of calcium carbonate.
| Classification | Hardness (mg/l CaCO3) | What you notice |
|---|---|---|
| Soft | Up to 100 | Easy lather, little scale, more corrosive to pipework |
| Slightly hard | 100 to 150 | Occasional light scale in the kettle |
| Moderately hard | 150 to 200 | Visible scale over time |
| Hard | 200 to 300 | Scale on heating elements, scum on tea, tide marks |
| Very hard | More than 300 | All of the above, faster |
The World Health Organisation guidance the Inspectorate cites puts the scale forming threshold at 200 mg/l. Above that line you are in the territory the Limescale Expert cartridge is sold for. BRITA’s own listing claims it is 50% more effective at removing limescale from tap water than the Pure Performance cartridge, and describes it as the filter for coffee and tea drinkers who want to protect their appliances. Below that line, in soft and slightly hard areas, you are paying extra for limescale performance you have little limescale to use it on.
There is a limit on what any jug can do here, and the Inspectorate states it plainly. Activated carbon jug filters that contain ion exchange resin beads alter the temporary hardness of water, so filtered water forms less scum on a cup of tea and may lay down less scale in a kettle. These devices do not alter the permanent hardness of the water. A jug is not a water softener and will not behave like one, whichever cartridge you put in it. Your water company publishes the hardness for your supply area and will send you a free water quality report for your address, which is worth reading before you commit to a cartridge subscription.
What a filtered litre actually costs
Both BRITA MAXTRA PRO cartridges are rated at up to 150 litres in four weeks. The Aqua Optima Evolve+ cartridge, which fits BRITA jugs as well as its own, is also rated at 150 litres. That makes the arithmetic straightforward, using the prices on Amazon UK this morning.
| Cartridge | Pack price today | Per cartridge | Rated litres | Cost per litre |
|---|---|---|---|---|
| Aqua Optima Evolve+, 4 pack | £11.99 | £3.00 | 150 | 2.0p |
| BRITA MAXTRA PRO Pure Performance, 6 pack | £22.68 | £3.78 | 150 | 2.5p |
| BRITA MAXTRA PRO Limescale Expert, 6 pack | £24.99 | £4.17 | 150 | 2.8p |
| Thames Water clean water charge, for comparison | £2.7346 per m³ | n/a | 1,000 | 0.27p |
So on a Thames Water meter the filtering costs between seven and ten times what the water itself costs. That is still a long way under bottled water, and it is the honest frame for the decision: you are buying a small improvement in taste and a reduction in kettle scale for a few pence a litre, on top of water that already meets the standards. Run the same sum for your own supplier using the volumetric rate on your bill. If you are working out the cost of what goes into a cup rather than what comes out of the tap, our coffee cost per cup index does the same exercise for coffee.
How we picked these
We started from the cartridge and worked back to the jug, because that is where the money and the maintenance live.
- Cartridge availability and price came first. A jug on an odd proprietary fitting is a jug whose running cost you cannot shop around on, so we favoured the two systems with the widest refill choice and included one long life alternative.
- Rated litres and change interval, taken from the manufacturer’s own listing. A cartridge rated for three months means fewer chances to miss a change, which is the failure mode the Inspectorate warns about.
- Fit. Filter jugs are usually kept in the fridge door, and several of these are sold on their width for that reason. We have given the dimensions where the listing states them.
- Prices are the single item Amazon UK price on the morning of 4 October 2026 and will move.
At a glance
| Jug | Best for | Capacity | Cartridge system | Price |
|---|---|---|---|---|
| BRITA Marella | Most homes | 2.4L | MAXTRA PRO | £19.99 |
| BRITA Marella XL | A household that drinks a lot | 3.5L | MAXTRA PRO | £19.49 |
| Waterdrop PT-07B Lucid | Fewest cartridge changes | 3.5L | WD-PF-01A Plus, 3 months | £15.49 |
| Aqua Optima Liscia | A narrow fridge shelf | 2.5L | Evolve+ | £9.99 |
| AQUAPHOR Compact | A cheap second jug | 2.4L | Maxfor+ | £10.99 |
| ZeroWater 10 Cup | Seeing what came out | 2.4L | ZeroWater 5 stage | £56.82 |
The six jugs
BRITA Marella, with 3 MAXTRA PRO Pure Performance cartridges
Best for most homesThis is the default British filter jug and the reason the MAXTRA PRO cartridges keep the chart positions they do. Buying the bundle with three cartridges included gets you about three months of filtering in the box, and the refills are stocked in every supermarket as well as online, so you are never stuck. It is the safe pick in soft and slightly hard areas, where the Pure Performance cartridge is the one you want.
The catch: the Pure Performance cartridge is the general purpose one, so if your supply is over 200 mg/l you are buying the weaker of the two BRITA options for limescale and will want the Limescale Expert refills instead, which cost a little more per litre.
2.4L jug, 3 cartridges included · around £20
Check price on Amazon →BRITA Marella XL, with 1 MAXTRA PRO Pure Performance cartridge
Best for a household that drinks a lotThe XL is the same filtration in a 3.5 litre body, which BRITA sells for high volume use. If there are three or four of you and the standard Marella is refilled five times a day, the larger reservoir saves you the trips to the tap. A single cartridge still gives 150 litres, so the bigger jug does not burn through refills any faster, it just means you wait less often.
The catch: it comes with one cartridge rather than three, so the first refill purchase arrives within a month, and the taller body will not fit every fridge door shelf. Measure before you order.
3.5L jug, 1 cartridge included · around £20
Check price on Amazon →Waterdrop PT-07B Lucid, 3.5L
Best for fewest cartridge changesWaterdrop rates its WD-PF-01A Plus cartridge at three months and 200 gallons against the four weeks of a MAXTRA PRO, and the filter is NSF 42 certified for chlorine, taste and odour reduction and NSF 372 certified as lead free in its materials. Given that the Inspectorate’s main warning is about cartridges left in too long, a filter you only have to think about four times a year has a real advantage over one you have to think about thirteen times. It carries a 4.6 star average from over 17,000 UK ratings.
The catch: the cartridge is proprietary and explicitly not a MAXTRA fit, so you cannot pick up a refill in a supermarket and the third party market for it is thinner. The 3.5 litre body is 13.5cm deep, which Waterdrop itself flags as too big for some fridge doors.
3.5L jug, 3 month NSF certified filter · around £15
Check price on Amazon →Aqua Optima Liscia, 2.5L
Best for a narrow fridge shelfAt 100mm deep this is the slimmest jug here, designed to stand in a fridge door without displacing the milk. It takes the Evolve+ cartridge, which is the cheapest of the 150 litre cartridges at 2.0p a litre and also fits BRITA jugs, so the running cost is the lowest of the mainstream systems. For under a tenner with a filter in the box it is the least you can spend to find out whether you like filtered water at all.
The catch: the 2.5 litre total capacity is only 1.2 litres of filtered water at a time, so a household of more than two will be refilling it constantly, and the slim body makes it top heavy when the reservoir is full.
2.5L total, 1.2L filtered, 1 cartridge · around £10
Check price on Amazon →AQUAPHOR Compact, 2.4L
Best for a cheap second jugAQUAPHOR is the quiet third option next to BRITA and Aqua Optima, and the Compact is aimed squarely at small households and students. It comes with a Maxfor+ cartridge and holds a 4.5 star average across more than 6,000 UK ratings, which is a decent showing for a jug at this money. It works well as a second jug for an office desk or a spare room kettle.
The catch: Maxfor+ cartridges are the hardest of these to find on a supermarket shelf, so you are committing to ordering refills online, and the brand’s UK stock can be patchy compared with BRITA.
2.4L jug, 1 Maxfor+ cartridge · around £11
Check price on Amazon →ZeroWater 10 Cup, 2.4L, with digital TDS meter
Best for seeing what came outZeroWater runs a five stage filter and ships a digital total dissolved solids meter in the box, so you can measure your tap water and then measure the filtered water and watch the number fall. It is the only jug here that lets you see anything at all, and the meter is also how you know the cartridge is spent rather than guessing from a calendar. That addresses the change interval problem from the other direction.
The catch: it is more than five times the price of the Aqua Optima, and stripping dissolved solids down towards zero takes out the calcium and magnesium too, which the Inspectorate notes has some limited evidence of a link to cardiovascular health. In a hard water area the cartridge will exhaust quickly and the refills are expensive.
2.4L jug, 5 stage filter, TDS meter included · around £57
Check price on Amazon →Frequently asked questions
Is UK tap water safe to drink without a filter?
Yes. The Drinking Water Inspectorate reported that public supplies in England met regulatory standards in 99.97% of tests in 2025, across more than 3.5 million samples. Its consumer guidance says there is no need to install additional treatment within the home as a health protection measure. The most common reason people buy a filter is to change the taste.
Which BRITA cartridge should I buy, Pure Performance or Limescale Expert?
It depends on your water hardness. The Inspectorate classes water above 200 mg/l of calcium carbonate as hard, and the World Health Organisation guidance it cites puts the scale forming threshold at the same figure. BRITA claims the Limescale Expert cartridge is 50% more effective at removing limescale than Pure Performance, so it suits hard and very hard areas. In soft or slightly hard areas the Pure Performance cartridge is the cheaper choice per litre. Your water company publishes the hardness for your postcode.
Does a filter jug soften water?
No. The Inspectorate says activated carbon jug filters containing ion exchange resin beads alter only the temporary hardness of water, which is the part that comes out as scale when you boil it. They do not alter the permanent hardness. A jug can reduce scum on tea and scale in a kettle, and it will not change how your water behaves in the shower or the washing machine.
What happens if I leave a cartridge in too long?
The Inspectorate’s guidance is specific about this. Failing to follow the manufacturer’s advice on maintenance and how often the cartridge is changed will cause a build up of deposits, create a breeding ground for bacteria, and cause removed material to leach back into the drinking water. Both MAXTRA PRO cartridges are rated at up to 150 litres in four weeks, and longer life filters exist if you know you will forget.
How much does filtering actually cost per litre?
Between 2.0p and 2.8p a litre at the prices on Amazon UK on 4 October 2026, working from cartridges rated at 150 litres each. The Aqua Optima Evolve+ four pack at £11.99 comes to 2.0p, the BRITA Pure Performance six pack at £22.68 comes to 2.5p, and the Limescale Expert six pack at £24.99 comes to 2.8p. Thames Water charges £2.7346 per cubic metre for clean water from April 2026, which is 0.27p a litre.
Will a filter remove lead from old pipes?
Lead in drinking water comes from lead pipes and internal plumbing in older properties, which is why the Inspectorate attributed 447 of the 982 compliance failures in 2025 to consumers’ own distribution systems. Both BRITA MAXTRA PRO cartridges list metals including lead among what they filter if present. The Inspectorate’s position is that the proper fix is replacing the pipework, and water companies have set an ambition to be lead pipe free by 2050. If you suspect lead pipes, ask your water company to test.
Sources
- Drinking Water Inspectorate, Chief Inspector’s Annual Report 2025 for England
- Drinking Water Inspectorate, Domestic water filters and softeners
- Drinking Water Inspectorate, Water hardness and hard water
- Thames Water, metered charges from 1 April 2026
- Amazon.co.uk Best Sellers, Home & Kitchen (chart positions)
- Amazon.co.uk, water filter jug search results (prices and product details)
Prices and chart positions were taken from Amazon.co.uk on 4 October 2026 and change often. Look Into earns a commission on Amazon purchases made through the links above, at no extra cost to you. That does not affect which products we include.