Head-to-head · Best Under-Sink Water Filters

Clearly Filtered 3-Stage Under the Sink vs Filtrete 3US-PS01

Which is the better buy? Side-by-side on rating, price, strengths, and watch-outs — with the published ratings we averaged to get there.

The short answer

Clearly Filtered 3-Stage Under the Sink comes out ahead by a narrow margin (4.5 vs 4.3). The gap is mostly about Buyers who want the widest contaminant reduction, including fluoride and PFAS, without reverse osmosis and don't mind paying a premium. — read the strengths below before deciding.

Higher ratedRanked #2 in Best Under-Sink Water Filters

Clearly Filtered 3-Stage Under the Sink

4.5

$495

The Clearly Filtered 3-Stage is the broad-spectrum carbon system, independently tested to reduce 232+ contaminants, including fluoride, lead, PFAS and arsenic, while keeping beneficial minerals and wasting no water. Its 2,000-gallon filter life is among the longest here. The catches are price (it's the costliest in this group) and that it carries only one full NSF certification despite extensive third-party testing. For maximum contaminant breadth without RO, it's excellent.

Strengths

— Independently tested to reduce 232+ contaminants including fluoride, lead, PFAS and arsenic
— Long 2,000-gallon filter life, roughly 9 to 15 months between changes
— Retains beneficial minerals, no water waste, no drain line or dedicated faucet needed

Watch-outs

— Holds only one full NSF certification (NSF 42) despite broad third-party testing
— Significantly more expensive upfront than other carbon systems
— Some owners report reduced water pressure over the filter's life

$495 · Check Price on Amazon Full review →

Ranked #5 in Best Under-Sink Water Filters

Filtrete 3US-PS01

4.3

$90

The Filtrete 3US-PS01 is 3M's straightforward under-sink filter, NSF/ANSI 42 and 53 certified to reduce chlorine taste and odor and parasitic cysts like Giardia and Cryptosporidium. Its signature Sanitary Quick Change cartridge installs with a quarter turn and no spills, and it uses your existing faucet at a strong 1.5 to 2.0 GPM. Filter life is a modest 2,000 gallons, and breadth is limited, but it's a reliable, widely available essential filter from a trusted brand.

Strengths

— NSF/ANSI 42 and 53 certified to reduce chlorine taste/odor and parasitic cysts
— Uses your existing faucet, no separate faucet or drilling required
— Sanitary Quick Change cartridge installs with a simple quarter turn, no spills

Watch-outs

— 2,000-gallon / 6-month filter life is shorter than the Waterdrop 15UA
— Single-cartridge system has limited contaminant breadth
— Initial line installation can be tricky for non-handy users

$90 · Check Price on Amazon Full review →

How they stack up

Clearly Filtered 3-Stage Under the Sink

Broader contaminant testing than the Aquasana Claryum AQ-5300+, Waterdrop 15UA and Filtrete 3US-PS01, with longer filter life, but at a much higher price and with fewer formal NSF certifications than the Aquasana. More comprehensive than the budget Frizzlife MP99.

Filtrete 3US-PS01

Similar essential-reduction scope to the Waterdrop 15UA and Frizzlife MP99 but with a shorter 2,000-gallon filter life than the Waterdrop. Less contaminant breadth and fewer certifications than the three-stage Aquasana Claryum AQ-5300+ and Clearly Filtered 3-Stage, but from the trusted 3M brand.

Specs side-by-side

Spec	Clearly Filtered 3-Stage Under the Sink	Filtrete 3US-PS01
Filtration	3-stage Affinity media	Single-stage, 0.5 micron
Certifications	NSF/ANSI 42, 372 (broad third-party testing)	NSF/ANSI 42, 53
Contaminants Reduced	232+ (fluoride, lead, PFAS, arsenic)	Chlorine taste/odor, parasitic cysts, sediment
Filter Life	2,000 gallons / 9-15 months	2,000 gallons / 6 months
Mineral Retention	Yes	—
Water Waste	None	—
Faucet	Uses existing faucet (no separate faucet)	Uses existing faucet
Reduction Rate	90-99% across tested contaminants	—
Flow Rate	—	1.5-2.0 GPM
Maintenance	—	Sanitary Quick Change (quarter turn)
Brand	—	3M Filtrete

← See the full ranking of best under-sink water filters