Water filter companies in the uk: how to compare technologies, prices and certifications

Tap water in the UK is often described as “one of the safest in the world”. Yet growing evidence around PFAS, microplastics and other emerging contaminants is pushing many households to look for extra protection. The result? A booming market of water filter companies, all promising “pure”, “chemical-free” or “PFAS-safe” water.

But how do you actually compare them? Which technologies genuinely reduce PFAS and other contaminants, and which are mostly marketing? And how do you weigh price, performance and certifications without needing a chemistry degree?

This guide walks you through a structured way to compare UK water filter companies – looking at technology, cost and third-party verification – so you can decide what is worth your money, and what is just clever branding.

Start with the real question: what do you want to remove?

Before diving into brands and models, it helps to be specific. “Cleaner water” means different things depending on your situation. In the UK, three main concerns keep coming up:

• PFAS (“forever chemicals”): Persistent, bioaccumulative, linked to immune, hormonal and developmental issues. Still not comprehensively regulated in UK drinking water.
• Disinfection by-products & chlorine: Created when chlorine reacts with organic matter. Usually within regulatory limits, but a frequent taste and odour complaint.
• Metals, limescale & plumbing-related contaminants: Lead from old pipes or solder, copper, and high hardness (limescale) in many UK regions.

Ideally, start with a recent water quality report from your local supplier and, if you can, a lab test of your tap water (especially if you have a private supply or very old plumbing). Not everyone will do this, but the clearer you are on your priorities, the easier it is to pick appropriate technology and avoid overpaying for features you don’t need.

Core filter technologies used by UK companies

Most domestic water filtration systems combine several technologies. When comparing companies, ignore the brand names for a moment and focus on what’s actually inside the filter.

Here are the main technologies you’ll see on the UK market.

Activated carbon (granular or block)

Activated carbon is the workhorse of domestic filtration.

• How it works: Adsorbs (binds) chemicals to the surface of highly porous carbon. Often made from coconut shell or coal.
• Best for: Chlorine, many disinfection by-products, some pesticides, many VOCs, some PFAS (especially long-chain PFAS), taste and odour.
• Limitations: Less effective for very small, highly soluble contaminants (like some short-chain PFAS), nitrates, most dissolved minerals, and heavy metals unless combined with additional media.
• Common formats: Jug filters, under-sink cartridges, fridge filters, whole-house carbon units.

When assessing companies:

• Look for solid carbon block rather than loose granular carbon in higher-end systems. Blocks provide more contact time and predictable performance.
• Ask whether the carbon is certified for PFAS reduction (more on certifications below) rather than just “tested for organics”.

Reverse osmosis (RO)

Reverse osmosis is often used by companies that market “the most thorough” filtration.

• How it works: Water is pushed under pressure through a semi-permeable membrane that rejects most dissolved salts, metals, many organic molecules, and some microorganisms.
• Best for: Many PFAS, heavy metals (lead, arsenic), nitrates, fluoride, some microplastics, and a broad range of other contaminants.
• Limitations: Wastes some water (the reject stream), slower flow, removes beneficial minerals (though many systems remineralise), typically under-sink only.

For PFAS specifically, high-quality RO membranes have shown strong removal rates for a range of compounds, including some short-chain PFAS that are more difficult to capture with carbon alone. If PFAS are your main concern, RO combined with carbon pre/post-filters is one of the most robust options currently available for domestic use.

Ion exchange resins

Ion exchange is increasingly used in PFAS-specific cartridges.

• How it works: Resin beads swap ions in water (e.g. calcium, magnesium, PFAS anions) with ions attached to the resin. For PFAS, specialised anion-exchange resins are used.
• Best for: Hardness (in softeners), some heavy metals, and – with the right resin – targeted PFAS removal.
• Limitations: Capacity is finite; resins saturate and must be replaced or regenerated. Performance is highly dependent on resin type and water chemistry.

Some UK companies now sell cartridges marketed explicitly as “PFAS filters” using proprietary resins. Here, independent lab data is non-negotiable. Do not rely on generic statements like “removes up to 99% of forever chemicals” without test reports.

Other technologies you may see

• Ultrafiltration / nanofiltration: Membrane systems with pores larger than RO but smaller than most microplastics and many pathogens. Nanofiltration can remove some PFAS; performance varies by membrane design.
• Distillation: Boils water and condenses the steam. Effective for many metals and salts; less convenient, slower and energy-intensive for daily drinking water.
• UV disinfection: Inactivates bacteria and viruses but does not remove PFAS or chemicals. Often paired with other technologies.

When a company advertises something “revolutionary”, it nearly always fits into one of these established categories. Ask which.

Which technologies are best for PFAS in UK tap water?

PFAS are chemically diverse, so no single household technology removes every compound equally well. However, current evidence points to three main approaches with proven potential:

• High-quality activated carbon (especially carbon block), with verified PFAS reduction data.
• Reverse osmosis, ideally combined with carbon pre/post-filtration.
• Specialised anion-exchange resins designed for PFAS, backed by independent lab testing.

For most UK homes, this translates into two realistic choices:

• An under-sink RO system with carbon stages for maximum contaminant coverage, including PFAS, metals and nitrates.
• A high-end under-sink carbon block system (sometimes with added ion exchange) for strong chemical reduction with less waste and simpler installation.

Jug filters, basic fridge filters and “taste and odour” cartridges may improve flavour, but they typically offer limited or unverified PFAS reduction. If a company sells mainly jug filters and uses “PFAS” heavily in its marketing, ask for actual test data before trusting those claims.

Understanding certifications: who checks the claims?

Words like “tested”, “certified” and “approved” are everywhere – but they don’t all mean the same thing. When comparing companies, it’s crucial to separate internal testing from independent, standard-based certification.

Key points to look for in the UK context:

• NSF/ANSI standards (common for international products):
  • NSF/ANSI 42: Aesthetic effects – chlorine, taste, odour, particulates.
  • NSF/ANSI 53: Health effects – heavy metals, some organic chemicals, some PFAS (if specifically listed).
  • NSF/ANSI 58: For reverse osmosis systems – performance of the RO membrane and system.
  • NSF/ANSI 401: “Emerging contaminants” – pharmaceuticals, certain PFAS and other modern contaminants.
  • NSF P473: A protocol specifically for PFOA and PFOS reduction (often integrated into other standards now).
• European / British standards:
  • BS EN 14898, BS EN 13443, etc.: Various standards for treatment devices (mainly mechanical, softening, etc.).
  • WRAS approval: Confirms a product is suitable for contact with UK drinking water from a plumbing perspective. It does not guarantee contaminant reduction.
  • DWI (Drinking Water Inspectorate) approval for certain technologies or materials used by suppliers – again, more about safety and materials than specific PFAS removal.

To interpret a company’s claims:

• Check if the product is certified to specific NSF/ANSI standards, not just “tested to NSF standards”. There is a difference between internal testing and formal certification.
• Look for certification scope: Does the NSF/ANSI 53 listing actually include PFAS compounds (PFOA, PFOS, others) or just lead and chlorine?
• Ask for independent lab reports if PFAS reduction is central to your decision. These should specify:
  • Which PFAS were tested.
  • Initial concentration and final concentration.
  • Number of litres filtered before breakthrough.
  • Test conditions (flow rate, temperature, pH).

A credible company will either have third-party certification or detailed lab reports available on request. If they refuse to share specifics or hide behind vague “proprietary testing”, treat that as a warning sign.

How to compare prices: look beyond the upfront cost

Most people fixate on the purchase price, but with water filters, lifetime cost is what really matters. When comparing UK companies, break it down into:

• System cost: The one-off cost of the unit (jug, under-sink, whole-house, countertop, RO, etc.).
• Filter replacement cost: How much each replacement cartridge or membrane costs.
• Replacement frequency: Stated in months, but ideally also in litres.
• Installation and plumbing: For plumbed-in systems – is it DIY-friendly, or do you need a professional installer?
• Running costs:
  • RO: Water waste ratio (e.g. 2:1 or 4:1) and any electricity use.
  • UV: Power consumption and lamp replacements.

A useful comparison metric is cost per litre of filtered water. Roughly estimate:

(Total annual cost of filters + any other consumables) ÷ (Total litres per year)

For example:

• Jug filter with £8 cartridges changed monthly, used for 4 litres/day:
  • Filter cost per year: £8 × 12 = £96
  • Water per year: 4 × 365 ≈ 1,460 litres
  • Cost per litre ≈ 6.6p (not counting the jug itself)
• Under-sink carbon block at £60 per cartridge, changed every 6 months, used for 10 litres/day:
  • Filter cost per year: £60 × 2 = £120
  • Water per year: 10 × 365 ≈ 3,650 litres
  • Cost per litre ≈ 3.3p

Suddenly that “cheap” jug doesn’t look so cheap. Many UK households are surprised to find that robust under-sink systems cost less per litre than jugs, especially when used by a family.

System types: what UK companies actually sell

Technology is one dimension; format is another. When evaluating companies, it helps to know which category they specialise in.

• Jug filters:
  • Pros: Low upfront cost, no plumbing, widely available.
  • Cons: Limited contaminant reduction, small capacity, frequent cartridge changes, variable PFAS performance.
• Under-sink systems (carbon or RO):
  • Pros: High performance, convenient dedicated tap, better cost per litre, hidden from view.
  • Cons: Installation required, space under sink, higher upfront cost.
• Countertop systems:
  • Pros: No permanent plumbing changes, moveable, good for renters.
  • Cons: Takes up counter space, appearance, some models have lower flow.
• Whole-house systems:
  • Pros: Treats all water entering the home – good for chlorine, odour, sometimes PFAS or hardness.
  • Cons: More complex, expensive, and not always necessary if your priority is just drinking water.

A company that only offers jugs is likely focused on volume and branding rather than advanced treatment. A company offering RO, under-sink carbon and possibly whole-house systems is usually more invested in technical performance and customisation.

Spotting red flags in marketing claims

Once you start comparing UK water filter companies, patterns appear in their marketing. Some are reassuring; others should make you pause.

Red flags to watch for:

• Vague “up to 99% removal” with no context:
  • “Up to” could mean under ideal lab conditions, for a single contaminant, at the start of filter life.
  • Always ask: which contaminant, from what starting concentration, and up to how many litres?
• No mention of independent testing:
  • “Lab tested” can mean an internal test once on a prototype.
  • Look for named labs, standards or certification bodies.
• Overpromising on viruses and bacteria from mains water:
  • UK mains water is already microbiologically treated and monitored.
  • If a company’s main selling point for UK customers is “kills 99.9999% of bacteria”, they may be mis-prioritising risks.
• Detox, anti-ageing or wellness claims:
  • Filters do not “alkalise your cells” or “reverse ageing”. They remove or reduce contaminants – which is important enough on its own.
• No clear cartridge life in litres:
  • “Lasts up to 6 months” is meaningless without usage assumptions.
  • Serious companies state recommended litres or give tables by household size.

On the positive side, reassuring signs include:

• Detailed technical datasheets available online.
• Clear breakdown of contaminants reduced, with standards or test reports cited.
• Honest acknowledgment of limitations (e.g. “this model does not remove nitrates; consider our RO system if nitrates are a concern”).

How to shortlist UK water filter companies: a practical approach

To move from theory to practice, here is a step-by-step way to compare companies without spending weeks on it.

• Define your priorities:
  • Are PFAS your main concern?
  • Do you also care about limescale, lead, or nitrates?
  • Is under-sink installation acceptable, or must it be “no tools”?
• Filter the market by technology:
  • Shortlist companies offering suitable technologies:
    • PFAS-focused: RO + carbon, high-end carbon block, or PFAS-specific ion exchange.
    • Limescale-focused: softening or anti-scale technologies plus drinking water filtration.
• Check certifications and test data:
  • Note any NSF/ANSI standards, WRAS approvals, or lab reports.
  • For PFAS, confirm specific compounds and reduction levels.
• Compare lifetime cost:
  • Estimate cost per litre for your household’s expected usage.
  • Include replacement cartridges, membranes, UV lamps and any expected servicing.
• Evaluate transparency and support:
  • Is technical information easy to find?
  • Do they answer specific questions about PFAS, UK regulations and testing?
  • Are installation instructions and videos clear?

After this exercise, the cheapest or flashiest option is rarely the one that still looks good. What tends to move up the list are companies that combine robust technology with open data and realistic claims.

Why independent verification matters more than ever

PFAS are reshaping the conversation around drinking water treatment. UK regulation is still catching up, and many water companies do not routinely report a wide spectrum of PFAS compounds. That regulatory gap creates space for good innovators – but also for opportunists.

This is why independent verification is so important. For a technology as invisible as water treatment, you are essentially trusting the company’s word that their filter is doing what they say. Certifications and third-party lab reports add an external voice to that promise.

At the same time, no domestic filter is a magic shield. Even the best RO system or PFAS-specific resin has a finite capacity and must be maintained. In that sense, buying a filter is less like buying a fridge and more like subscribing to a routine: you are choosing an ongoing relationship with the company’s technology, support and transparency.

When you compare UK water filter companies with that in mind – looking at technologies, prices per litre and, critically, certifications and data – the decision becomes less about chasing the “best” gadget and more about finding a partner you actually trust to stand between you and contaminants you cannot see.