AO Smith Under Sink Water Filter System - Reduces PFAS, Lead

In this review the AO Smith Under Sink Water Filter System is evaluated for everyday kitchen use; it is best for households seeking a dedicated faucet with reliable contaminant reduction without losing essential minerals. The single biggest reason to consider it is the system's targeted filtration that reduces PFAS (PFOA and PFOS), lead and chlorine while remaining certified to NSF/ANSI standards, making it a straightforward way to improve drinking water quality without a complex install. Installation uses the included tee and tubing to tap a 3/8 in cold water line and an extra faucet so filtered water is always available.

Key Features

• Dedicated faucet setup: Includes an additional faucet and tubing that connect to a 3/8 in threaded cold water supply line for clean water without disturbing your main tap.
• Broad contaminant reduction: Designed to reduce 99% of 78 harmful contaminants such as lead, PFAS (PFOA and PFOS), chlorine, mercury and asbestos while leaving beneficial minerals intact.
• NSF/ANSI certified system: The full system is WQA tested and certified to NSF/ANSI standards 42, 43 and 401, ensuring overall structural and performance integrity.
• Two-stage Claryum filtration: Uses a two-stage approach to address taste and health-related contaminants without adding chemicals or wasting water.
• Low maintenance: Filter life is approximately six months or 500 gallons, keeping annual maintenance costs generally under $120.
• Decent flow rate: Filters water at roughly 0.5 gallons per minute, suitable for filling pitchers and glasses quickly for small families.

Who It's For

The system is a good match for individuals or families of one to four who want an under-sink solution that delivers improved taste and reduced health risks from contaminants like lead and PFAS without professional plumbing. It is also appropriate for renters or homeowners who prefer a dedicated drinking faucet that installs in minutes using the included fittings and tubing.

Those who need very high flow for large kitchens, commercial use, or instantaneous whole-house treatment should look elsewhere, as the AO Smith under sink unit is optimized for point-of-use drinking water with a modest flow rate and a six-month filter cadence.

Pros & Cons

Pros

• Removes a wide range of contaminants including PFAS, lead and chlorine while leaving minerals in the water.
• Easy DIY installation with included tee and tubing, no plumber required for most users.
• System certified to NSF/ANSI standards 42, 43 and 401 for verified performance and construction quality.
• Cost efficient operation with no water waste and a reasonable annual maintenance cost.

Cons

• Flow rate is modest at about 0.5 gallons per minute, which may feel slow for some users or larger households.
• A small number of users have reported occasional leakage issues, so careful installation and periodic checks are advisable.

Specifications

Brand	AO Smith
Filtration type	Under-sink, 2-stage Claryum filtration
Contaminants reduced	PFAS (PFOA, PFOS), lead, chlorine, mercury, asbestos, pharmaceuticals, chloramine
Flow rate	0.5 gallons per minute
Filter life	6 months / 500 gallons
Certifications	NSF/ANSI 42, 43, 401 (WQA tested)
Installation	Connects to 3/8 in threaded cold water supply with included tee and tubing

Our Verdict

The AO Smith Under Sink Water Filter System is a sensible choice for smaller households seeking certified contaminant reduction, including PFAS and lead, delivered through a dedicated faucet and an easy DIY install. It offers reliable taste improvement and verified performance at a reasonable maintenance cost, though users wanting higher flow or whole-house coverage should consider alternate solutions.

Frequently Asked Questions

How often does the filter need changing?
The filter is rated for about six months or 500 gallons, depending on water use and local water quality.

Will this system remove essential minerals?
No, the system is designed to reduce harmful contaminants while leaving beneficial minerals in the water.

Is a plumber required for installation?
No, the system includes a tee and tubing for connection to a 3/8 in cold water supply and an extra faucet, so most users can install it themselves.