A decent water filter jug costs as little as £15.00 and can noticeably improve the taste of chlorinated tap water — a real concern in hard-water areas like London, the South East, and the East Midlands. This guide covers the three main filter types, what the specs actually mean, and which products are worth your money right now.
What to look for
01Jug capacity and fridge fit
Most filter jugs sold in the UK hold between 2. 5L and 3.5L total, but the 'filtered water' capacity is always lower once you account for the upper reservoir. The Aqua Optima Liscia and Waterdrop PT-05B are both 2.5L models, which slip easily onto a standard fridge shelf without fouling the door seal. The BRITA Marella XL steps up to 3.5L — useful if you drink a lot of hot drinks or cook with filtered water regularly, but measure your fridge shelf depth first: most standard UK larder fridges have shelves around 400–450mm deep, and a tall jug can prevent the door closing properly. If space is tight, a 2.5L jug is the safer call.
02Filter cartridge running costs
The upfront jug price is almost irrelevant compared to what you spend on replacement cartridges over a year. A single BRITA MAXTRA PRO Pure Performance cartridge lasts roughly four weeks, so you need around 12 per year. Buying a 12-pack at £39.93 works out to about £3.33 per month. The FilterLogic Universal 6-pack at £12.49 (compatible with BRITA MAXTRA+ jugs) cuts that cost significantly — roughly £2.08 per month if you buy two packs annually. The Waterdrop PT-05B uses a 3-month cartridge, which reduces how often you need to remember to reorder. Always check compatibility before buying third-party cartridges: FilterLogic explicitly lists Marella, Elemaris, and Bosch Tassimo compatibility on the packaging.
03What filters actually remove
In hard-water areas — roughly 60% of England — limescale is the primary concern. Calcium and magnesium ions fur up your kettle element and affect tea flavour. BRITA's MAXTRA PRO Limescale Expert cartridge is specifically formulated to tackle this, making it a smart choice if you live in London or the Home Counties. For broader protection, the BRITA MAXTRA PRO Pure Performance filter also reduces chlorine, PFAS, and pesticide traces — all certified to NSF standards. The Waterdrop PT-05B carries NSF certification too. If you're on a soft-water supply (most of Scotland, Wales, and the North West), a standard chlorine-reduction filter is usually sufficient and you can save money on the more specialist cartridges.
04Tap and under-sink systems: when a jug is not enough
Filter jugs suit most households, but they have limits. You refill them manually, they hold only a few litres, and they need cartridge changes every four to twelve weeks. Under-sink systems connect to your cold-water supply and feed a dedicated tap, delivering filtered water at full mains pressure. They cost considerably more upfront and require basic plumbing, but running costs per litre are often lower. For most renters and flat-dwellers in the UK, a quality jug remains the most practical and affordable starting point.
05Price tracking and when to buy
Water filter prices fluctuate more than you might expect. The BRITA Marella XL (blue) has ranged from £13.00 to £19.99 over the past 90 days — a £6.99 swing on a sub-£20 product. The Aqua Optima Liscia with six filters has swung between £15.00 and £22.00. Buying at the 90-day low can save you 30% or more. Cartridge multipacks also dip regularly: the BRITA MAXTRA PRO Pure Performance 12-pack has been as low as £34.99 against a high of £43.88. Setting a price alert on Amazon or checking back monthly is worth the small effort given how frequently these products are discounted.
Our top picks
Best for budget-conscious first-time buyersAqua Optima by LAICA Liscia Water
At £15.00 — and with a 90-day low of just £9.00 — the Aqua Optima Liscia 2.5L is the most affordable complete starter kit here. It comes with three Evolve+ filter cartridges, is dishwasher-friendly, and fits standard UK fridge shelves without trouble. If you want to try filtered water without committing much money, this is the obvious place to start.
Best value jug-and-filter bundleAqua Optima Liscia Water Filter Jug
The Aqua Optima Liscia with six Evolve+ cartridges at £17.60 gives you roughly six months of filtered water in one purchase. The 90-day low is £15.00, so it is worth watching for a dip. At 2.5L it fits neatly in the fridge door, and the easy-fill lid means you are not wrestling with it every time. Six cartridges upfront also means fewer reorder reminders — a genuine convenience for busy households.
Best for NSF-certified filtration on a small budgetWaterdrop PT-05B Elfin Water Filter Jug
The Waterdrop PT-05B Elfin costs £19.99 but has dropped to £12.59 in the past 90 days, so a price alert is worthwhile. Its 3-month cartridge lifespan is the longest in this group, cutting down on replacement frequency. NSF certification gives it credibility beyond most budget jugs.
Best larger jug for families and heavy tea drinkersBRITA Water Filter Jug MAXTRA Marella
The BRITA Marella XL in blue holds 3.5L and currently sits at £18.99, having dropped as low as £13.00 over the past 90 days. It uses BRITA's MAXTRA PRO Pure Performance cartridge, which reduces chlorine, PFAS, and limescale — useful in hard-water areas across the South East. The larger reservoir means fewer refills per day, which matters if you are making multiple rounds of tea or cooking with filtered water regularly.
Best cartridge multipack for BRITA jug ownersBRITA MAXTRA PRO Pure Performance Water
If you already own a BRITA jug, the MAXTRA PRO Pure Performance 12-pack at £39.93 (90-day low: £34.99) covers a full year of replacements in one order. Each cartridge reduces chlorine, PFAS, pesticides, and limescale — the Pure Performance formula is BRITA's broadest-spectrum option. Buying 12 at once works out to around £3.33 per cartridge, cheaper than buying individually and one less thing to forget.
Best cartridge for hard-water areasBRITA Water Filter Cartridge MAXTRA PRO
The BRITA MAXTRA PRO Limescale Expert 3-pack at £13.99 (90-day low: £8.99) is specifically engineered for households in hard-water regions — think London, the Thames Valley, and East Anglia, where calcium deposits fur up kettles quickly. If your kettle element is regularly coated in white scale, this is the cartridge to switch to.
Best third-party cartridge for cutting running costsFilterLogic Universal 6 Pack Filter Cartridges
FilterLogic's Universal 6-pack at £12.49 — the same as its 90-day low — is compatible with BRITA MAXTRA+, MAXTRA Pro, Marella, Elemaris, and Bosch Tassimo machines. Six cartridges for £12.49 works out to roughly £2.08 each, compared to over £3.30 for genuine BRITA cartridges. A straightforward way to halve your annual filter spend without changing your jug.
Frequently asked
How often should I change my water filter cartridge in the UK?
Most standard filter cartridges, including BRITA MAXTRA PRO, are rated for approximately four weeks or 100–150 litres of filtered water. In a hard-water area such as London or the South East, the cartridge may exhaust faster because it is working harder to remove calcium and magnesium. The Waterdrop PT-05B uses a 3-month cartridge, which is more convenient. As a practical rule: 1. Check the manufacturer's guidance for your specific cartridge. 2. Replace sooner if you notice a change in taste or slower flow through the filter. 3. Never leave a cartridge in place for more than the stated maximum, even if usage is low, as bacteria can accumulate.
Are third-party filter cartridges like FilterLogic as good as genuine BRITA ones?
They reduce chlorine and limescale in the same way as genuine cartridges. The main difference is that BRITA's own MAXTRA PRO Pure Performance cartridge also targets PFAS and pesticides, which FilterLogic does not specifically claim. For everyday taste improvement and limescale reduction in a hard-water area, third-party cartridges are a reasonable and significantly cheaper choice. If you want the broadest certified filtration, stick with genuine BRITA cartridges.
Will a 3.5L filter jug fit in a standard UK fridge?
It depends on your fridge model. Most standard UK larder fridges and fridge-freezers have internal shelf depths of around 400–450mm, and a 3.5L jug such as the BRITA Marella XL is taller than a 2.5L model. The main risk is that a tall jug prevents the fridge door from closing properly, particularly if you store it on a door shelf. Before buying, measure the clearance between your fridge shelf and the shelf above it, and check the jug's stated height in the product dimensions. A 2.5L jug is a safer fit for most compact or integrated UK fridges.
Do I need a special water filter if I live in a hard-water area?
Not necessarily a different type of filter, but a different cartridge formulation can help. BRITA's MAXTRA PRO Limescale Expert cartridge is specifically designed for hard-water regions and does a more thorough job of removing calcium and magnesium ions than a standard cartridge. If you live in London, the South East, East Anglia, or the East Midlands — all classified as hard or very hard water zones by UK water companies — it is worth choosing a cartridge that explicitly targets limescale. You will also need to replace cartridges more frequently than the stated maximum, as the resin exhausts faster when mineral content is high.
What is the cheapest way to filter tap water in the UK?
A filter jug is the most affordable entry point. The Aqua Optima Liscia 2.5L with three cartridges costs £15.00 at current prices and has been as low as £9.00 in the past 90 days. Ongoing costs depend on cartridge choice: FilterLogic's Universal 6-pack at £12.49 works out to roughly £2.08 per cartridge, which is the lowest cost-per-cartridge option in this group. Avoiding single-cartridge purchases and buying multipacks is the single biggest saving. Tap-mounted and under-sink systems cost more upfront but can be cheaper per litre over several years if you use large volumes of filtered water daily.