Best under sink water filter UK: 3 brands compared (and which one to choose)
- 2 days ago
- 6 min read
Updated: 1 hour ago
If you’re searching for the best under sink water filter in the UK, you’re probably trying to fix one (or all) of these:
water that doesn’t taste quite right
limescale building up in your kettle
the hassle of constantly refilling filter jugs
Quick picks: best under sink water filters (UK)
Best for purest water: Waterdrop G2P600
Best all-round: Maverick Mav 02
Best budget anti-scale: UK Water Filters inline anti-scale filter
An under sink filter can solve all three — giving you filtered water straight from the tap, without the daily effort.
Not all under sink filters do the same job
Most under sink filters are designed to improve taste and reduce common impurities — which is what a lot of people are looking for.
But in the UK, there’s often another factor in the background: hard water.
In many areas, minerals like calcium and magnesium are present in the water supply. These don’t just affect taste — they’re what cause limescale in kettles, taps and appliances.
The important thing to know is that not all filters deal with this in the same way.
Some reduce a broad range of contaminants.
Some just reduce how quickly limescale builds up.
And some remove minerals almost completely.
Understanding that difference makes it much easier to choose the right filter for your home.
Why choose an under sink water filter?
At the plumbing company I also run, we’ve seen a sharp rise in customers asking about under sink and reverse osmosis systems. People are becoming much more aware of their water — both for taste and for health.
Filter jugs have been popular for years, but they’re heavy, slow and manual.
Under sink filters are different. Once installed, they quietly do the job in the background — no refilling, no waiting around.
The main benefits include:
filtered water straight from the tap
better-tasting drinking water
more consistent, long-term filtration
less day-to-day effort compared to jugs
the potential to reduce limescale buildup (depending on the system)
If you live in a hard water area, that last point becomes especially important. Not all filters make a noticeable difference to limescale — so in this guide, we’ve focused on options that are more effective in that area.
Let's dive in.
1. Waterdrop G2P600 (reverse osmosis)
Best under sink water filter for maximum filtration: Waterdrop G2P600
If you want the purest possible drinking water — and to reduce limescale in your kettle or coffee machine as much as possible — reverse osmosis is the most effective option.
We’ve actually fitted this system at Plumberly, and it’s a really compact, well-designed setup that works well in a typical UK under sink cupboard.
The Waterdrop G2P600 removes a wide range of dissolved substances — including the minerals that cause limescale — giving you:
very clean, neutral-tasting water
broad contaminant removal (including fluoride and minerals)
minimal to no scale buildup in kettles and appliances
It’s a more advanced system, so installation is more involved than an inline filter. You’ll need space under your sink and a separate tap, but once it’s in, it’s a very effective, low-maintenance setup.
In terms of cost, you’re looking at around £300 for the system. If you’re not confident with DIY, it’s worth budgeting an extra £200 for professional installation.
Like all reverse osmosis systems, it does produce some wastewater (although this is one of the most efficient models), so that’s something to be aware of.
But if you’re fed up with constant descaling and want the most complete solution, this is the only type of system that actually removes hardness minerals — which is what makes the biggest difference long term.
Best for:
Homes that want the purest water possible and minimal limescale
Not ideal for:
Anyone looking for a quick install or lower upfront cost
2. Maverick undersink filter
Best all-round under sink water filter: Maverick Mav 02
If you’re looking for a practical, everyday solution, Maverick is one of the best under sink water filters in the UK right now — offering a great balance of performance, price and ease of installation.
It connects to your cold water supply and uses a multi-stage filtration system to improve water quality and help manage limescale.
In real-world use, that means:
noticeably better-tasting water
less visible limescale in kettles
a broad range of contaminants reduced
What makes it such a strong all-round option is that balance. It’s more capable than a simple inline filter, but much easier (and cheaper) than a full reverse osmosis system.
It reduces fluoride, lead, microplastics, chlorine and if you have hard water, there’s also a dedicated anti-scale stage that works by changing how minerals behave. This helps reduce how aggressively limescale forms — rather than removing those minerals completely.
That’s actually a benefit for many people, as those minerals (like calcium and magnesium) are good for you and remain in the water.
Installation is straightforward, and ongoing filter costs are low — making it a sensible long-term upgrade.
To get started you're looking at around £110 and ongoing filters are just £50 a year (making it considerably cheaper than alternative brand Water2).
Best for:
Homes that want a noticeable upgrade in water quality without the cost or complexity of an RO system
Not ideal for:
Anyone looking to completely eliminate hard water minerals
3. Inline anti-scale filter
Best inline filter for budget anti-scaling: UK Water Filters inline anti-scale filter
If you’re searching for the best inline filter specifically for limescale reduction, this is a great no-frills, low-cost option.
It’s a small cartridge that connects directly to your cold water line using standard fittings, focusing on improving taste and helping reduce limescale buildup.
It doesn't claim to eliminate other contaminants from your water, like microplastics or chlorine, but if limescale in your kettle is your only concern, this may be the one for you.
At around £25 per filter (lasting 6 months), you’re looking at an annual cost of about £50. That said, results can vary depending on your local water, so in harder areas you may find the cartridge needs replacing a little sooner.
Best for:
Low-cost, limescale reduction only
Not ideal for:
Anyone who wants the benefit of broader contaminant removal
Best under sink filter comparison
Feature | Waterdrop G2P600 | Maverick Mav 02 | Inline anti-scale filter |
Best for | Maximum filtration | All-round performance | Budget anti-scaling |
Price first year | £300 | £110 | £50 |
Ongoing annual costs | £76/year (plus electricity + wastewater) | £50/year | £50/year |
Limescale impact | Removes minerals completely | Slows buildup up to 99% | Slows buildup for 95% of customers |
Broader contaminant removal | Maximum | Excellent | None |
Installation | Moderate – plumber needed | Easy | Easy |
Available from |
So, which is the best under sink water filter for you?
It depends on what you’re trying to fix.
If you want a cheap fix for limescale buildup, go with an inline filter
If you want the best all-round under sink filter, Maverick is the sweet spot
If you want to remove limescale almost completely, choose reverse osmosis
Under sink filter alternatives
Under sink filters aren’t your only choice. Depending on your setup, you might also want to look at:
on-tap filters (quick to install)
worktop RO systems (no plumbing required and healthy minerals can be added back in)
Thinking about filtering your shower water too?
Did you know hard water doesn’t just affect your kettle — it can impact your skin and hair too? Common complaints from showering in hard water include:
dry or tight-feeling skin after showering
hair that feels rough, dull or harder to manage
products like shampoo and shower gel not lathering as well
So if you’re looking into an under sink filter, it’s worth considering a shower filter too.
Shower filters don’t remove hard water minerals completely, but they can help improve how the water feels on your skin and hair — which is why many people notice softer hair and less irritation after switching.
Read more Best shower filters for hard water
Author bio: Lucinda Smalley is the founder of Hard Water Home, a UK-based consumer site helping households in hard water areas understand the challenges and solutions more easily — and make smarter choices for their health and homes. Based in Poole, she also co-runs an award-winning plumbing company, giving her first-hand insight into how water quality affects everything from appliances to skin and hair. When she’s not writing, she’s happiest at the beach with her family and a good cup of coffee (minus the floaty bits!). More about us ➡
