There are four main types of water filters for UK homes: activated carbon, reverse osmosis, UV, and water softeners. Each removes different contaminants, costs different amounts, and solves different problems. Here's everything you need to know to choose the right one. All removal rates are based on NSF International testing standards. New to water filtration? Start with the basics.
| Feature | Activated Carbon | Reverse Osmosis (RO) | Ceramic | UV Sterilizer | Water Softener |
|---|---|---|---|---|---|
| Best For | Chlorine, taste, odor | Lead, PFAS, microplastics | Bacteria, cysts, off-grid | Bacteria, viruses | Hard water, limescale |
| Upfront Cost | £50-200 | £250-500 | £150-300 | £150-400 | £400-1,500 |
| Annual Running Cost | £30-60 | £54-120 | £60-120 | £20-40 | £80-150 |
| Pressure Required | Any (1+ bar) | High (3+ bar) | None (gravity) or 1+ bar | Any (1+ bar) | Any (1+ bar) |
| Wastes Water | No | Yes (4:1 ratio) | No | No | Yes (regeneration) |
| Maintenance | Easy (replace every 6-12 months) | Moderate (multiple filters) | Moderate (clean monthly, replace 6 months) | Easy (bulb yearly) | Moderate (salt refills) |
| Installation | DIY friendly | Professional recommended | DIY friendly (gravity) or moderate (under-sink) | DIY friendly | Professional required |
The most common and affordable option
Activated carbon is charcoal that's been treated to create millions of tiny pores. Water flows through these pores, and contaminants stick to the carbon surface through a process called adsorption. Think of it like a molecular sponge—chemicals and particles get trapped while water passes through. Effectiveness varies based on NSF certification level.
Households primarily concerned about chlorine taste/odor, or those in areas with good baseline water quality who want to improve taste. Ideal for renters or those on a budget. Perfect for London and South East England where chlorine levels are high.
Pre-1970 homes with lead pipes, areas with bacterial contamination, or households concerned about PFAS/microplastics. Carbon filters won't solve hard water problems or protect against heavy metals.
Initial cost: £50-200 (filter + installation)
Replacement filters: £30-60/year × 10 years = £300-600
Total 10-year cost: £350-800
The most comprehensive filtration
RO systems force water through a semi-permeable membrane with pores 0.0001 microns wide—1,000 times smaller than a human hair, small enough to block virtually everything except water molecules. It's like pushing water through an incredibly fine mesh that catches contaminants at the molecular level.
At the time of writing, no home testing kits exist for PFAS or microplastics. These contaminants require specialized laboratory equipment to detect.
Scotland has mandatory PFAS testing (0.1 µg/L limit) since January 2023. England has voluntary guidelines only. You can contact your water company to ask about their PFAS testing frequency and results—find contact details via Ofwat.
For removal: Reverse osmosis is the gold standard—90-99% PFAS removal, 99%+ microplastics removal. Specialized activated carbon can remove 50-90% of PFAS, but standard carbon filters provide minimal removal (10-30%).
Pre-1970 homes with lead pipes, households concerned about PFAS/microplastics, areas with agricultural runoff (nitrates), or anyone wanting the most comprehensive filtration. Particularly valuable for unmetered households (37.3% of UK) where waste water costs nothing. Ideal for families with young children or immunocompromised members.
Top-floor flats with low water pressure (unless you install a £180-600 booster pump), metered households on a tight budget (waste water adds £54-108/year), or those who need high flow rates for cooking. Won't solve hard water/limescale problems—you'd need a softener too.
Unmetered Household:
Initial cost: £350-700 (system + installation)
Replacement filters: £60-100/year × 10 years = £600-1,000
Waste water: £0
Total 10-year cost: £950-1,700
Metered Household:
Initial cost: £350-700
Replacement filters: £600-1,000
Waste water: £54-108/year × 10 years = £540-1,080
Total 10-year cost: £1,490-2,780
Kills bacteria and viruses without chemicals
UV sterilizers expose water to ultraviolet light at 254 nanometers wavelength, which damages the DNA of bacteria, viruses, and other microorganisms, preventing them from reproducing. The water flows past a UV bulb in a chamber—no chemicals, no filters to replace (just the bulb annually).
Private wells, rural areas with bacterial concerns, or as a backup during boil water notices. Often combined with carbon or RO systems for comprehensive protection. Useful in areas prone to contamination incidents like the Brixham cryptosporidium outbreak (May 2024).
Mains water in areas with good baseline quality (UK mains water is already 99.98% compliant when it leaves treatment works). UV doesn't improve taste, remove chemicals, or solve hard water problems. Most UK households don't need UV unless they have a private well or specific contamination concerns.
Initial cost: £150-400 (unit + installation)
UV bulb replacement: £20-40/year × 10 years = £200-400
Electricity: £15-25/year × 10 years = £150-250
Total 10-year cost: £500-1,050
Removes hard water minerals (calcium, magnesium)
Water softeners use ion exchange resin beads that swap calcium and magnesium ions (hard water minerals) for sodium ions. The resin eventually becomes saturated and needs regeneration—flushing with salt water to recharge the beads. This is a whole-house system, not point-of-use.
Benefits: No limescale buildup on taps, kettles, appliances. Softer skin and hair. Less soap and detergent needed. Longer appliance lifespan.
Important: Softened water contains more sodium (salt is used in the ion exchange process to replace calcium and magnesium). Thames Water advises against drinking softened water, especially for babies and those on low-sodium diets. Excess sodium can contribute to high blood pressure and cardiovascular issues in sensitive individuals. If you have a softener, install a separate tap for drinking water or use an RO filter (which removes sodium).
Hard water areas (London, South East, East Anglia) where limescale is a major problem. Protects appliances (washing machines, dishwashers, boilers), reduces cleaning time, and improves skin/hair feel. Often combined with a drinking water filter (carbon or RO) for comprehensive protection.
Soft water areas (Scotland, North West England, Wales) where hardness isn't a problem. Renters (requires professional installation and plumbing modifications). Those on low-sodium diets. Doesn't improve drinking water safety or taste—you'd need a separate drinking water filter.
Initial cost: £400-1,500 (system + professional installation)
Salt: £80-120/year × 10 years = £800-1,200
Electricity: £15-30/year × 10 years = £150-300
Maintenance: £50-100/year × 10 years = £500-1,000
Total 10-year cost: £1,850-4,000
Note: Savings from reduced appliance repairs and longer lifespan can offset costs over time.
Do you have hard water (London, South East, East Anglia)?
→ Water Softener for whole house + Carbon or RO for drinking water
Do you have lead pipes (pre-1970 home)?
→ Reverse Osmosis (100% lead removal - TechGearLab verified)
Concerned about PFAS or microplastics?
→ Reverse Osmosis (90-99% PFAS, 99%+ microplastics)
Just want to improve chlorine taste/odor?
→ Activated Carbon (cheapest, simplest solution)
Private well or bacterial concerns?
→ UV Sterilizer + Carbon or RO for chemicals
Want comprehensive protection?
→ RO System (removes virtually everything) or Carbon + UV combination
Water characteristics: Very hard (300+ mg/L), high chlorine, potential lead pipes in older areas—check your postcode
Recommended:
Water characteristics: Soft water, potential copper/lead leaching in old pipes
Recommended:
Water characteristics: Very soft, excellent baseline quality, mostly unmetered
Recommended:
Water characteristics: Hard water, agricultural runoff (nitrates), some lead pipes
Recommended:
Natural filtration for gravity systems and countertops
Ceramic water filters use microporous ceramic material (diatomaceous earth) to physically filter out contaminants. The tiny pores (0.5-0.9 microns absolute) trap bacteria, protozoa, sediment, and particles—think of it as a 3D sieve that catches anything too large to pass through. Many ceramic filters include an activated carbon core for improved taste and chemical reduction, plus optional media for lead, fluoride, or heavy metals. Doulton and British Berkefeld are the main UK manufacturers with NSF certification.
Off-grid living, well water users, emergency preparedness (no electricity needed), and renters who prefer countertop gravity systems. Ideal for microbiologically unsafe water (bacteria, cysts) or those who want natural materials over plastic. Popular UK brands include Doulton (Staffordshire-based, 200-year heritage) and British Berkefeld.
Slow flow rate (gravity systems: 1L/hour per filter), requires regular cleaning (scrub ceramic shell monthly to maintain flow), fragile (ceramic can crack if dropped), and doesn't remove viruses (pores too large at 0.5 micron). Gravity systems need countertop space. Not ideal for hard water areas (doesn't remove TDS/hardness).
British Berkefeld Ultra Sterasyl filters are NSF 42, 53, 372, and 401 certified—one of the few gravity filters with comprehensive certification. Doulton filters are NSF 42/53 certified and WRAS approved for UK plumbing compliance. Always verify certification in the NSF database before purchasing.
Initial cost: £150-300 (gravity system with 2 filters)
Replacement cartridges: £60-120/year × 10 years = £600-1,200
Electricity: £0 (gravity systems)
Water waste: £0 (no waste water)
Total 10-year cost: £750-1,500
Cost per litre: 0.3-0.6p (based on 2,300L per cartridge)
Ceramic filters are a niche but active market in the UK. Amazon UK sells approximately 3,000 ceramic filter units monthly, primarily for gravity systems (British Berkefeld, Doulton) and replacement cartridges. They're more popular than you might expect, especially among the off-grid and preparedness communities. Cleanable/reusable ceramic shells make them cost-effective for long-term use.
Critical information for hard water areas
If you live in a hard water area (London, Southeast, East Anglia, Yorkshire) and install an RO system WITHOUT a water softener, you're setting yourself up for expensive filter replacements. Hard water contains calcium and magnesium that form limescale, clogging your RO membrane and reducing its lifespan from 4-5 years to just 2-3 years—or even 12-18 months in very hard water areas.
RO membranes have microscopic pores (0.0001 microns) that are incredibly sensitive to scale buildup. When hard water passes through, calcium and magnesium crystallize on the membrane surface, clogging pores and reducing flow rate. The membrane has to work harder, uses more water, and eventually fails prematurely.
A water softener removes calcium and magnesium BEFORE they reach the RO membrane, protecting it from scale damage. The RO system then removes the small amount of sodium added by the softener, giving you pure, soft, sodium-free drinking water.
✅ Correct Order:
Mains Water → Water Softener → RO System → Drinking Tap
❌ Wrong Order:
Mains Water → RO System → Water Softener (Don't do this!)
Use our Water Quality Lookup Tool to check your local water hardness.
RO Membrane Lifespan (Hard Water):
Annual Savings: £50-100/year on RO filter replacements alone
Plus: Protected appliances (boiler, washing machine, dishwasher), no limescale buildup, softer skin/hair
If you have hard water (>150 ppm) and want an RO system, budget for BOTH a water softener (£400-1,500) and RO system (£250-500). Installing RO alone in hard water areas is a false economy—you'll spend more on premature filter replacements than you saved by skipping the softener.
RO systems need 40+ PSI (3+ bar) to work. Top-floor flats often have 1-2 bar. Test your pressure first or you'll need a £180-600 booster pump. Read our complete RO cost guide.
Carbon filters only remove 3.8% of lead (TechGearLab verified) - not effective for lead concerns. They DO remove 93% of PFAS, which is good. For lead pipes, you need RO (100% lead removal).
Scotland, North West England, and Wales already have soft water. A softener won't help and adds unnecessary sodium to your water.
RO wastes 4 litres per 1 litre filtered. If you're metered, that's £54-108/year extra on your water bill. Factor this into your decision. See full cost breakdown.
UV only kills microorganisms. It doesn't remove chlorine, improve taste, or protect against chemicals. Most UK mains water doesn't need UV.
Expired filters don't just stop working—they can release trapped contaminants back into your water. Set calendar reminders for replacements.
From basic taste improvement to complete home protection — see what each level removes
Basic chlorine & taste improvement
Chlorine, taste & basic contaminants
Lead, PFAS, microplastics & more
Near-complete contaminant removal
Every tap protected + appliance life
💡 Most UK homes benefit from Level 2-3. Lead pipes or health concerns? Consider Level 3-4.
Lead is the #1 water quality concern in UK homes built before 1970. These guides will help you understand the risks and solutions.
Lead often isn't the only concern. Many UK homes face multiple water quality issues.
Learn the basics of how water filters work and when you actually need one.
The hidden cost of RO waste water and why 37.3% of UK households have an advantage.
Why the UK doesn't test for PFAS and which filters remove these "forever chemicals."