A water filter jug can cost as little as £9.00 to buy, but the ongoing cartridge bill is what catches most UK shoppers off guard. Replacement filters typically need swapping every four to eight weeks, so your annual spend on refills can easily outstrip the jug's purchase price two or three times over.
What to look for
01Cartridge lifespan and how often you'll replace
Most filter cartridges are rated for around four weeks of use, though some stretch to eight weeks. That gap matters enormously for your annual budget. A four-week cartridge used year-round means roughly 13 replacements; an eight-week one cuts that to about six. The Waterdrop PT-05B ships with a 90-day filter, which is one of the longer lifespans in this category and reduces how frequently you're ordering replacements. In hard-water areas such as London, the South East, and the East Midlands, cartridges can exhaust faster because they're working harder to reduce limescale, so treat manufacturer estimates as a best case rather than a guarantee.
02Cost per cartridge versus cost per pack
Buying in bulk almost always lowers your per-cartridge cost, but you need to match pack size to your actual usage. The FilterLogic Universal 6-pack is currently £12.49, which works out at roughly £2.08 per cartridge. The BRITA MAXTRA PRO Pure Performance 12-pack is £39.93, or about £3.33 each, but these are original BRITA refills with PFAS and pesticide reduction claims that the third-party alternatives do not make. The BRITA MAXTRA PRO Limescale Expert 3-pack sits at £13.99, around £4.66 per cartridge, reflecting its specialist hard-water formula. If you live in a soft-water area such as Scotland or Wales, the standard Pure Performance cartridge is likely sufficient and the 12-pack gives the best per-unit value. In a hard-water area, the Limescale Expert variant may protect your kettle and appliances more effectively, potentially saving on descaling products.
03Annual running cost: worked examples
To make the maths concrete: if you replace a cartridge every four weeks, you need 13 per year. At FilterLogic's £2.08 per cartridge, that is roughly £27.00 annually. Using BRITA MAXTRA PRO Pure Performance at £3.33 each, the same schedule costs around £43.00. Stretch to an eight-week replacement cycle and those figures halve to approximately £13.50 and £21.50 respectively. The jug itself is a one-off cost: the Aqua Optima Liscia with 3 cartridges is currently £14.99, and the 6-cartridge bundle is £22.00, which already covers roughly six months of filters. The BRITA Marella XL (3.5L) starts at £18.99 and includes one MAXTRA PRO cartridge. Factor in the jug price only in year one; from year two, your spend is cartridges alone.
04Jug capacity and household size
A 2. 5L jug such as the Waterdrop PT-05B or Aqua Optima Liscia suits one or two people comfortably. A 3.5L jug like the BRITA Marella XL is better for three or four people, reducing how often you refill and potentially extending cartridge life in calendar terms because you filter a similar volume over more days. UK kitchen worktops and fridge door shelves are typically designed around standard 600mm-deep units, and a 2.5L jug fits most fridge door compartments without issue. The Marella XL's larger footprint may not fit every fridge shelf, so measure your shelf height before buying. A bigger jug does not reduce your annual cartridge cost, but it does reduce the inconvenience of frequent refilling.
05Third-party versus original cartridges
Third-party cartridges compatible with BRITA jugs, such as the FilterLogic Universal 6-pack at £12. 49, can cut your annual filter bill significantly compared with original BRITA refills. The trade-off is that third-party filters may not carry the same NSF certification or PFAS-reduction claims as the originals. BRITA's MAXTRA PRO Pure Performance explicitly states it reduces PFAS and pesticides, which third-party alternatives typically do not claim. For most UK tap water, which already meets legal safety standards, the practical difference in day-to-day taste and limescale reduction is often minimal. However, if you have specific concerns about water quality in your area, checking your local water company's annual report and choosing a certified filter is the more cautious approach.
Our top picks
Best for keeping annual cartridge costs lowFilterLogic Universal 6 Pack Filter Cartridges
At £12.49 for a 6-pack, the FilterLogic Universal cartridges work out at roughly £2.08 each, the lowest per-unit cost in this selection. They are compatible with BRITA Maxtra+, Maxtra Pro, and Marella jugs, so you can use them with hardware you may already own. If you replace filters every four weeks, your annual spend is around £27.00. That is a meaningful saving over original BRITA refills for households where basic chlorine and limescale reduction is all that is needed.
Best original cartridge for hard-water areasBRITA MAXTRA PRO Pure Performance Water
Currently £39.93 for a 12-pack (down from a 90-day high of £43.88), the BRITA MAXTRA PRO Pure Performance works out at around £3.33 per cartridge. It is the only filter here that explicitly claims to reduce PFAS and pesticides alongside chlorine and limescale, making it the strongest choice for households in London or the South East where water hardness and trace contaminants are a genuine concern.
Best starter bundle for first-time buyersAqua Optima Liscia Water Filter Jug
The Aqua Optima Liscia with 3 Evolve+ cartridges is currently £14.99, having hit a 90-day low of £9.00, so it represents strong value even at full price. The bundle covers roughly three months of filtering straight out of the box, and the 2.5L jug is both dishwasher-friendly and fridge-friendly, fitting standard UK fridge door shelves. It is a practical, low-commitment entry point before you commit to a particular cartridge ecosystem.
Best for infrequent cartridge changesWaterdrop PT-05B Elfin Water Filter Jug
The Waterdrop PT-05B is NSF certified and ships with a single 90-day filter, one of the longest replacement intervals in this category. At £19.99 (its 90-day low was £12.59), the 2.5L BPA-free jug reduces lead, fluoride, and chlorine. If you dislike the admin of frequent filter orders, a 90-day cycle means just four cartridge changes per year, keeping your annual maintenance effort and cost manageable.
Best large-capacity jug for familiesBRITA Marella XL Water Filter Jug
The BRITA Marella XL holds 3.5L, making it one of the larger jugs in this group and well suited to households of three or four people. At £18.99 (90-day low was £13.00), it includes one MAXTRA PRO Pure Performance cartridge and features a digital filter-change indicator so you are not guessing when to reorder. The flip-lid design makes one-handed refilling straightforward at the kitchen sink.
Best cartridge for protecting kettles in hard-water areasBRITA MAXTRA PRO Limescale Expert Water
The BRITA MAXTRA PRO Limescale Expert 3-pack is £13.99 and is specifically formulated to reduce limescale more aggressively than the standard Pure Performance cartridge. If you live in a hard-water area such as the South East or East Midlands, limescale build-up inside your kettle and coffee machine is a real cost, shortening appliance life.
Frequently asked
How much does a water filter cost per year in the UK?
Your annual running cost depends on cartridge price and how often you replace. Using FilterLogic Universal cartridges at roughly £2.08 each and swapping every four weeks, you spend around £27.00 per year. With original BRITA MAXTRA PRO Pure Performance at about £3.33 each on the same schedule, the cost rises to around £43.00. Stretch to an eight-week replacement cycle and both figures roughly halve. Add the jug purchase price only in year one; from year two, cartridges are your only recurring expense.
Are third-party water filter cartridges as good as BRITA originals?
Third-party cartridges compatible with BRITA jugs, such as the FilterLogic Universal 6-pack at £12.49, reduce chlorine and limescale effectively for most UK tap water. The key difference is certification: BRITA MAXTRA PRO Pure Performance cartridges carry explicit claims for reducing PFAS and pesticides, which third-party alternatives typically do not make. For everyday taste improvement and limescale reduction in a soft-water area, third-party filters are a reasonable choice. In a hard-water area or if you have specific water-quality concerns, original BRITA cartridges offer more documented reassurance.
How often should I change my water filter cartridge?
Most manufacturers recommend every four weeks, but this is a conservative estimate based on average household use. In hard-water areas such as London or the South East, cartridges exhaust faster. Some jugs, including the BRITA Marella XL, include a digital indicator to take the guesswork out. The Waterdrop PT-05B ships with a 90-day filter, one of the longer intervals available.
Will a water filter jug fit in my fridge?
Most 2.5L jugs, including the Waterdrop PT-05B and Aqua Optima Liscia, are designed to fit standard UK fridge door shelves. Measure your shelf height before buying a larger model: the BRITA Marella XL holds 3.5L and has a taller profile that may not fit every fridge door compartment. Both the Aqua Optima Liscia and the Marella XL are explicitly described as fridge-friendly by their manufacturers, but checking your fridge's internal dimensions against the jug's height is always worth doing.
Is it cheaper to buy water filter cartridges in bulk?
Generally yes. The BRITA MAXTRA PRO Pure Performance 12-pack at £39.93 works out at around £3.33 per cartridge, compared with buying smaller packs more frequently at a higher per-unit cost. The Aqua Optima Liscia 6-cartridge bundle at £22.00 offers better value than the 3-cartridge version at £14.99, which works out at £5.00 per cartridge versus roughly £3.67 each. The main risk with bulk buying is cartridges expiring before use, so only buy in quantities you will realistically use within 12 months.