BBy Bikram Nath·Researched from UK Amazon listings·Updated 2026-10-17·6 products compared
Disclosure: As an Amazon Associate I earn from qualifying purchases. This guide contains Amazon affiliate links, and we may earn a commission — at no extra cost to you — but it never changes our rankings.
What are the best under sink water filters to buy in the UK?
Our top pick for Under Sink Water Filters in the UK is the Frizzlife SK99 Under Sink Water Filter System, NSF/ANSI 53&42 Certified.
The Frizzlife SK99 suits buyers who want NSF/ANSI 53&42 named in the title, a 0.5 micron carbon block and a stated guarantee of 3 years at maximum; the listing gives no filter life figure.
The Frizzlife SK99 under sink water filter is our top pick because its listing states NSF/ANSI 53&42 certification, a 0.5 micron carbon block, a flow rate of over 2.0GPM at 60 psi and a guarantee of 3 years at maximum. For a system with several filters, the Waterdrop TSA lists 3 filters and 8-stage filtration with lifespans of 6 months, 8-12 months and 12-18 months; for a single in-line cartridge with braided hoses, the AQUA CREST 5KDC lists 12 months or 18,927 gallons.
This guide compares six under sink water filters from Frizzlife, Waterdrop, iSpring, AQUA CREST and SY GOODLIFE, using what each listing states: certification, filtration media and stages, filter life, flow rate, fittings, TDS and warranty. Among the four listings that give a capacity in gallons, figures run from 8000 gallons on the SY GOODLIFE to 18,927 gallons on the AQUA CREST 5KDC.
Buying guide
What should you look for in Under Sink Water Filters?
1Certification: the Frizzlife SK99 title states NSF/ANSI 53&42 Certified and the SY GOODLIFE title NSF 42&53 Certified; the Waterdrop TSA title states NSF/ANSI 42 Certified and the iSpring US31 title NSF/ANSI 58 Certified. The Waterdrop 10UA listing says it is certified by IAPMO against NSF/ANSI 372 and refers to the ANSI 42 standard for chlorine, taste and odour. The AQUA CREST 5KDC listing refers to NSF standards without naming a standard number.
2Filter life: the Waterdrop TSA gives 6 months, 8-12 months and 12-18 months for its three filters; the Waterdrop 10UA a maximum of 12 months or 11000 gallons; the AQUA CREST 5KDC 12 months or 18,927 gallons; the iSpring US31 up to 12 months and 10,000 gallons; the SY GOODLIFE up to 8000 gallons with a maximum of 12 months. The Frizzlife SK99 listing gives no filter life figure.
3Flow rate: the listings state over 2.0GPM at 60 psi (Frizzlife SK99), 3 litres per minute at 60 psi (Waterdrop 10UA), 1.5 gpm (AQUA CREST 5KDC) and 1 GPM (iSpring US31). The Waterdrop TSA and SY GOODLIFE listings give no flow figure.
4TDS and minerals: the Frizzlife SK99, Waterdrop TSA and AQUA CREST 5KDC listings say they do not reduce TDS (total dissolved solids). The Waterdrop 10UA listing points buyers who want to reduce water hardness or TDS to an RO system, the SY GOODLIFE listing says it retains beneficial minerals, and the iSpring US31 listing does not mention TDS.
5Warranty: the Frizzlife SK99 listing says it is guaranteed for 3 years at maximum. The Waterdrop TSA, Waterdrop 10UA, iSpring US31, AQUA CREST 5KDC and SY GOODLIFE listings state no warranty term.
Our process
How do we choose our picks?
We don’t lab-test products ourselves. Instead we synthesise current Amazon UK listings and published specs into clear, honest recommendations. We earn a commission if you buy through our links, but that never changes which products we rank.
Current UK availability
We check each pick against live Amazon UK catalogue data rather than last year’s model lists. Stock moves fast, so a listing can sell out after we publish.
Published specs
We compare manufacturer specifications so each pick is right for a real budget and use-case.
UK-specific fit
We factor in UK voltage and plug/fitting standards — details that generic global lists miss.
IAPMO certified against NSF/ANSI 372; ANSI 42 standard for chlorine, taste and odour (per…
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NSF/ANSI 42&53 (per listing)
Filter Life
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6 months, 8-12 months and 12-18 months for the three filters
Up to 12 months; 10,000 gallon
Maximum 12 months or 11000 gallons
12 months or 18,927 gallons
Up to 8000 gallons; maximum 12 months
Fitting
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Push-to-connect; 3/8" and 1/2" cold water tubes
Push-to-connect; 1/2" and 3/8" cold water tubes
Push-to-connect; 3/8" hose and 3/8"–1/2" convertor fitting
3/8” braided stainless steel inlet and outlet hoses; fits standard 3/8” water valves
In-line, connects to the cold water line; no tools required
Flow Rate
>2.0GPM @60 psi
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1 GPM
3 litres per minute at 60 psi
1.5 gpm
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TDS
Does not reduce TDS
Will not reduce TDS
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Will not reduce TDS
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The rankings
The best Under Sink Water Filters, ranked
1
FRIZZLIFE
Top Pick
Frizzlife SK99 Under Sink Water Filter System, NSF/ANSI 53&42 Certified
The Frizzlife SK99 suits buyers who want NSF/ANSI 53&42 named in the title, a 0.5 micron carbon block and a stated guarantee of 3 years at maximum; the listing gives no filter life figure.
Certification
NSF/ANSI 53&42 (title)
Filtration
0.5 micron carbon block; more than 7 layers of filtration materials
Flow Rate
>2.0GPM @60 psi
Warranty
Guaranteed for 3 years at maximum
TDS
Does not reduce TDS
What we like
+NSF/ANSI 53&42 certification named in the title
+States a 0.5 micron carbon block, and filter cartridges with more than 7 layers of filtration materials
+States a flow rate of over 2.0GPM at 60 psi
+Filter changes replace only the core filters inside, not the plastic housing, per the listing
Worth noting
–The listing gives no filter life in months or gallons
–The listing says it does not reduce TDS
–The listing does not say what the 3-year guarantee covers
£129.99Amazon.co.uk price as of 03 Nov, 18:00 (London time). Details
Waterdrop TSA 8-Layer Under Sink Water Filter System
The Waterdrop TSA suits buyers who want a three-filter, 8-stage system with stated filter lifespans and NSF/ANSI 42 in the title; the listing gives no flow rate or warranty term.
iSpring US31 3-Stage Under Sink Water Filter System
The iSpring US31 suits buyers who want a three-stage system with its own brushed nickel faucet, NSF/ANSI 58 in the title and a stated 1 GPM flow; the listing states no warranty term.
Certification
NSF/ANSI 58 (title)
Filtration
3-stage: PP, GAC and CTO
Filter Life
Up to 12 months; 10,000 gallon
Flow Rate
1 GPM
Fitting
Push-to-connect; 1/2" and 3/8" cold water tubes
Faucet
Brushed nickel faucet included, secured from above the countertop
What we like
+NSF/ANSI 58 certification named in the title
+Names its three stages: PP, GAC and CTO
+Comes with a brushed nickel faucet and a transparent first-stage housing for checking the filter, per the listing
+Push-to-connect fittings for 1/2" and 3/8" cold water tubes
Worth noting
–The listing states no warranty term
–The listing does not mention TDS (total dissolved solids)
£94.22£123.99−24%Amazon.co.uk price as of 03 Nov, 18:00 (London time). Details
Waterdrop 10UA Under Sink Water Filter System, 11000 Gallons
The Waterdrop 10UA suits buyers who want a multistage system with a stated 12 months or 11000 gallons and 3 litres per minute at 60 psi; the listing states no warranty term.
Certification
IAPMO certified against NSF/ANSI 372; ANSI 42 standard for chlorine, taste and odour (per listing)
Filtration
Multistage filtration
Filter Life
Maximum 12 months or 11000 gallons
Flow Rate
3 litres per minute at 60 psi
Fitting
Push-to-connect; 3/8" hose and 3/8"–1/2" convertor fitting
Materials
BPA-free and lead-free (per listing)
What we like
+States a maximum service life of 12 months or 11000 gallons per filter when used with municipal water
+States a full flow rate of 3 litres per minute at 60 psi
+Includes a 3/8" hose and a 3/8"–1/2" convertor fitting for 1/2" and 3/8" cold water lines
+The listing says its certification can be looked up on the IAPMO website under WD-10UA
Worth noting
–The listing states no warranty term
–The listing says multistage filtration but does not list the stages
–The listing says the system should be connected only to a cold water supply
£59.48£69.99−15%Amazon.co.uk price as of 03 Nov, 18:00 (London time). Details
AQUA CREST 5KDC Under Sink Inline Water Filtration System
The AQUA CREST 5KDC suits buyers who want an in-line cartridge with braided stainless steel hoses and a stated 12 months or 18,927 gallons; the listing names no NSF standard number and no warranty term.
Filtration
Coconut shell activated carbon with 0.5 μm filtration accuracy; KDF
Filter Life
12 months or 18,927 gallons
Flow Rate
1.5 gpm
Fitting
3/8” braided stainless steel inlet and outlet hoses; fits standard 3/8” water valves
Chlorine Reduction
97.6% of chlorine, taste and odour against NSF standards (per listing)
TDS
Will not reduce TDS
What we like
+States a service life of 12 months or 18,927 gallons
+States a flow rate of 1.5 gpm
+Packing list includes 3/8” braided stainless steel inlet and outlet hoses, clips, screws and cable ties
+The listing says installation takes 5 minutes without drilling holes or cutting hoses
Worth noting
–The listing refers to NSF standards without naming a standard number
–The listing states no warranty term
–The listing says it will not reduce TDS
£29.99Amazon.co.uk price as of 03 Nov, 18:00 (London time). Details
SY GOODLIFE Q5-MF Under Sink Water Filter, 8000 Gallon
The SY GOODLIFE Q5-MF suits buyers who want NSF/ANSI 42&53 certification and an auto shut-off valve for filter changes, with up to 8000 gallons or 12 months per filter; the listing gives no flow rate or warranty term.
Certification
NSF/ANSI 42&53 (per listing)
Filtration
Two-stage compound filter
Filter Life
Up to 8000 gallons; maximum 12 months
Fitting
In-line, connects to the cold water line; no tools required
Shutoff Valve
Integrated auto shut-off valve for filter changes
What we like
+NSF/ANSI 42&53 certification named on the listing
+Integrated auto shut-off valve, so the listing says the main water supply need not be switched off for filter changes
+Tool-free cartridge replacement in 3 seconds, per the listing
+The listing says installation takes three minutes
Worth noting
–The listing gives no flow rate figure
–The listing states no warranty term
£50.99Amazon.co.uk price as of 03 Nov, 18:00 (London time). Details
Product prices and availability are accurate as of 03 Nov, 18:00 (London time) and are subject to change. Any price and availability information displayed on Amazon.co.uk at the time of purchase will apply to the purchase of this product.
Editor's Note
Five of the six listings give a filter life; the Frizzlife SK99 does not, and it is also the one listing here that states a guarantee term. Flow figures come in different units (GPM, gpm and litres per minute), and the Waterdrop TSA and SY GOODLIFE listings give none. Contaminant reduction figures on these listings, such as lead or chlorine percentages, are the brands' own statements alongside the certifications they name.
Our Take
As a default, pick the Frizzlife SK99: NSF/ANSI 53&42 in its title, a 0.5 micron carbon block and a guarantee of 3 years at maximum, all on the listing. For stated lifespans on each of three filters, the Waterdrop TSA; for an in-line cartridge with braided stainless steel hoses and 12 months or 18,927 gallons, the AQUA CREST 5KDC.
Questions & answers
Frequently asked questions
Which under sink water filters state NSF certification?
The Frizzlife SK99 (NSF/ANSI 53&42), SY GOODLIFE (NSF 42&53), Waterdrop TSA (NSF/ANSI 42) and iSpring US31 (NSF/ANSI 58) name NSF certification in their titles. The Waterdrop 10UA listing says it is certified by IAPMO against NSF/ANSI 372.
How long do under sink water filter cartridges last?
The Waterdrop 10UA, AQUA CREST 5KDC, iSpring US31 and SY GOODLIFE listings each state up to 12 months per filter. The Waterdrop TSA gives 6 months, 8-12 months and 12-18 months for its three filters, and the Frizzlife SK99 listing gives no figure.
Do under sink water filters reduce TDS?
The Frizzlife SK99, Waterdrop TSA and AQUA CREST 5KDC listings say they do not reduce TDS. The SY GOODLIFE listing says it retains beneficial minerals, and the iSpring US31 listing does not mention TDS.
What flow rate do under sink water filters give?
The Frizzlife SK99 lists over 2.0GPM at 60 psi, the Waterdrop 10UA 3 litres per minute at 60 psi, the AQUA CREST 5KDC 1.5 gpm and the iSpring US31 1 GPM. The Waterdrop TSA and SY GOODLIFE listings give no flow figure.
Which under sink water filters fit 3/8" and 1/2" water lines?
The Waterdrop TSA, Waterdrop 10UA and iSpring US31 listings state compatibility with 3/8" and 1/2" cold water lines or tubes. The AQUA CREST 5KDC listing says its hoses fit standard 3/8" water valves under kitchen and bathroom sinks.
How long does an under sink water filter take to install?
The Waterdrop TSA and Waterdrop 10UA listings say installation with push-to-connect fittings takes less than 3 minutes, and the SY GOODLIFE listing says three minutes with no tools. The AQUA CREST 5KDC listing says 5 minutes without drilling holes or cutting hoses, and the Frizzlife SK99 listing says less than 15 minutes.
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