The right water filter jug size depends on how many people use it daily. A 2.5 L jug like the Waterdrop Elfin covers one or two people comfortably, while a 3.5 L Brita Marella XL suits a household of four. Prices on Amazon UK currently run from £12.49 for a six-pack of replacement cartridges to £39.93 for a 12-pack of Brita MAXTRA PRO filters.
What to look for
01Jug capacity and how many people it serves
The most important number on any filter jug is its total capacity, not just the filtered reservoir. A 2.5 L jug such as the Waterdrop PT-05B Elfin holds roughly 1.5 L of filtered water at a time once you account for the filter cartridge and unfiltered upper tank. That is fine for one or two people who refill once or twice a day. Step up to a 3.5 L jug, like either Brita Marella XL variant, and you get closer to 2.5 L of ready-to-drink water, which comfortably covers a family of three or four without constant refilling. Bear in mind that larger jugs may not fit on a standard 240 mm fridge shelf door, so measure your fridge shelf height before buying. The Brita Marella XL is specifically designed to lie on its side in a fridge, which helps with taller jugs in compact UK fridge-freezers.
02Filter cartridge lifespan and running cost
Capacity is not just about the jug volume; it also refers to how many litres each cartridge filters before replacement. Most Brita MAXTRA PRO cartridges are rated for up to 150 L, which equates to roughly four weeks of use for an average UK household. Buying in bulk reduces the per-cartridge cost significantly. The Brita MAXTRA PRO Pure Performance 12-pack works out at around £3.33 per cartridge at its current price of £39.93, compared with roughly £4.50 per cartridge if you buy the three-pack. The FilterLogic FL402H six-pack, compatible with Brita MAXTRA+ jugs, costs just £12.49 and has not dropped below that price in 90 days, making it a consistent budget option. If you live in a hard-water area such as London, the South East, or the East Midlands, the MAXTRA PRO Limescale Expert variant is worth the small premium, as it uses additional ion-exchange resin to tackle calcium and magnesium more aggressively.
03Filter type: limescale vs. all-round performance
Brita splits its MAXTRA PRO range into two distinct cartridge types. Pure Performance targets chlorine, PFAS, and pesticides alongside limescale, making it the better all-round choice for most UK tap water. Limescale Expert concentrates its ion-exchange capacity on calcium and magnesium, which is ideal if your primary complaint is scale build-up in your kettle or a chalky taste in hot drinks. The six-pack of Limescale Expert (ASIN B0C9JRN5T4) currently costs £23.40, down from a 90-day high of £25.99, so it is a reasonable time to stock up. Third-party cartridges such as the FilterLogic FL402H fit Brita MAXTRA+ jugs and cost considerably less, though they are not produced by Brita and carry their own NSF-style certifications rather than Brita's own testing data.
04Jug footprint and kitchen storage
UK kitchens are often compact, and a large filter jug can dominate a worktop or refuse to fit in a standard 300 mm wide cupboard. The Waterdrop Elfin at 2.5 L has a slim, upright profile designed to slot into a fridge door shelf, which is useful if worktop space is limited. The Brita Marella (2.4 L, ASIN B0BSXDHN2D) is similarly modest in footprint and comes with three Pure Performance cartridges in the box, giving you roughly three months of filtered water before you need to reorder. The Marella XL at 3.5 L is noticeably taller and wider; check that your fridge has a shelf at least 280 mm tall if you plan to store it upright. If you are replacing an existing jug, note that all Brita Marella models use MAXTRA+ or MAXTRA PRO cartridges, so you can switch between jug sizes without changing your cartridge subscription.
Our top picks
Best for one or two people on a tight budgetWaterdrop PT-05B Elfin Water Filter Jug
At £16.99 (with a 90-day low of £12.59), the Waterdrop PT-05B Elfin is the most affordable complete jug in this group. Its 2.5 L capacity and NSF-certified filter cartridge rated for three months of use make it a practical choice for a single person or couple. The slim profile fits neatly in a fridge door shelf, freeing up worktop space in smaller UK kitchens.
Best large jug for families of three or fourBRITA Water Filter Jug MAXTRA Marella
The Brita Marella XL in blue currently sits at £19.99, but its 90-day low was £13.00, so it is worth watching for a price drop. The 3.5 L capacity means fewer refills per day for a busy household, and the jug is designed to lie flat on a fridge shelf, which suits the shallow door shelves common in UK fridge-freezers. One Pure Performance cartridge is included.
Best starter kit with cartridges includedBRITA Water Filter Jug MAXTRA Marella
At £19.99, the Brita Marella 2.4 L white jug bundles three Pure Performance cartridges in the box, covering roughly three months of use straight away. That makes the effective cost per cartridge lower than buying separately. Its compact footprint suits a 300 mm kitchen cupboard, and the MAXTRA PRO format means you can switch to Limescale Expert cartridges if you move to a hard-water area.
Best value replacement cartridges for Brita jug ownersFilterLogic FL402H | 6X Filter Cartridge
The FilterLogic FL402H six-pack costs £12.49 and has held that price for the full 90-day window, making it the most price-stable product in this group. Each cartridge is compatible with Brita MAXTRA+ jugs, so if you already own a Marella or similar model, this is a straightforward way to cut your annual filter spend without changing hardware.
Best cartridge bulk-buy for hard-water householdsBRITA Water Filter Cartridge MAXTRA PRO
The Brita MAXTRA PRO Limescale Expert six-pack is currently £23.40, down from a 90-day high of £25.99. If you live in London, the South East, or another hard-water region, the extra ion-exchange resin in these cartridges tackles calcium and magnesium more effectively than the standard Pure Performance variant, helping to extend the life of your kettle and improve the taste of hot drinks.
Frequently asked
What size water filter jug do I need for a family of four?
A 3.5 L jug is the practical minimum for four people. At that capacity you get roughly 2.5 L of filtered water ready to drink at any one time, which covers a full kettle fill plus a couple of glasses without an immediate refill. The Brita Marella XL at £19.99 is the most widely available 3.5 L option in the UK. If your household drinks a lot of water or uses filtered water for cooking, consider keeping two jugs on rotation.
Are third-party Brita-compatible cartridges as good as genuine Brita filters?
Third-party cartridges such as the FilterLogic FL402H are designed to fit Brita MAXTRA+ jugs and carry their own filtration certifications, but they are not tested or endorsed by Brita. In practice, many UK buyers find them perfectly adequate for reducing chlorine taste and basic impurities. However, if you are specifically concerned about PFAS, pesticides, or heavy limescale in a hard-water area, the genuine Brita MAXTRA PRO Pure Performance or Limescale Expert cartridges have more detailed published test data to back up their claims.
How often should I change my water filter cartridge in the UK?
Most Brita MAXTRA PRO cartridges are rated for 150 L or approximately four weeks, whichever comes first. For a single person drinking two litres a day, that stretches closer to ten weeks. For a family of four using three to four litres daily, you will hit the 150 L limit in five to six weeks. If you live in a hard-water area, replace cartridges at the lower end of the range because the ion-exchange resin saturates faster with high mineral content.
Will a 3.5 L filter jug fit in my fridge?
It depends on your fridge model. The Brita Marella XL is designed to lie on its side on a fridge shelf, which requires a shelf at least 280 mm tall and around 300 mm deep. Many standard UK fridge-freezers have a shelf that accommodates this, but compact under-counter models may not. Measure your tallest available shelf before ordering. If space is tight, the 2.5 L Waterdrop Elfin or 2.4 L Brita Marella are slimmer alternatives that fit more easily in a fridge door shelf.
Which Brita cartridge is best for hard water in London or the South East?
The Brita MAXTRA PRO Limescale Expert is the better choice for hard-water areas. It uses a higher proportion of ion-exchange resin compared with the Pure Performance variant, which prioritises organic contaminants and PFAS. The six-pack (£23.40) works out at £3.90 per cartridge, and the three-pack (£13.49) is useful if you want to try it before committing. Both packs fit any Brita MAXTRA+ or MAXTRA PRO compatible jug.