Under-Sink Water Filters With a Faucet: Brands Sorted by Faucet Type

A filtered drinking tap of its own comes in the box with the Viomi Under-Sink Carbon Filter, a system that needs no power in the cabinet.

When the tap should also show what the system is doing, the LCD smart faucet on the Viomi V8 PRO displays purified-water TDS and filter life at the sink. Tank-based RO systems from iSpring and APEC keep to a standard RO faucet, and if you would rather keep the faucet you have, a direct-connect filter sends filtered water through it instead.

Brands and Models by Faucet Type

Every Viomi system in the table ships with its faucet, so the faucet, its fittings and the tubing arrive together.

Carbon Filters That Ship With a Drinking Faucet

A carbon filter with a dedicated faucet adds a separate drinking tap without any wiring or drain work. The Viomi Under-Sink Carbon Filter connects to the cold-water supply through an included three-way ball valve and sends filtered water up to its own faucet. The main kitchen faucet stays on regular tap water for washing up, and the drinking tap is there for glasses, kettles and cooking pots. There is a single 2-in-1 cartridge to replace, and each one lasts up to 12 months.

At change time, the cartridge twists out and a new one locks in without tools, a change that takes about 3 seconds. It runs on water pressure alone, so the drinking tap works without any power in the cabinet. Our guide to filter brands for chlorine removal covers what carbon is built to reduce. If a second tap isn't wanted, the Viomi Under-Sink Water Filtration System (VM-IUO1PCW-L-US) uses the same cartridge and connects to the cold line feeding the faucet you already have. Its 3/8-inch hoses fit standard 3/8-inch feed valves, and an included 3/8 to 1/2-inch adapter covers 1/2-inch lines. With the existing faucet doing the pouring, the counter stays exactly as it is. That suits a recently renovated kitchen, where the faucet was chosen to match the sink, the counter and the rest of the hardware. The Waterdrop 15UA and Aquasana Claryum Direct Connect (AQ-MF-1) work the same way.

How RO Brands Supply the Drinking Faucet

Purified water from an under-sink RO system reaches the counter through its own drinking faucet, and the brands differ in what that faucet is: a standard tap, a display faucet or a choice of your own. On tank-based systems such as the iSpring RCC7 and APEC ROES-50, the faucet draws from a storage tank; on tankless systems such as the Viomi RO models, water is purified as the faucet opens.

Each of the four Viomi RO models also comes with a step-by-step installation video. That faucet is the smart display faucet on the Viomi V6 PRO, Viomi V8 PRO and Viomi M1, linked to the main unit, so the same tap pours the water and reports what the system is doing.

Tank-based systems from iSpring and APEC come with a plain drinking tap, and APEC's standard RO faucet for the ROES-50 takes a 1/2-inch hole, or a 1-inch hole with an air-gap faucet. The Viomi B6W and Aquasana's SmartFlow RO leave the faucet style open: the Viomi B6W accepts a compatible faucet of your own alongside its included one, and the SmartFlow RO comes with a "No Faucet" option beside its all-metal dedicated faucet. Dealer systems bring their own options, including Culligan's ClearLink PRO, which switches the existing faucet between RO and tap water, and the lead-free tap of Kinetico's K5 Drinking Water Station.

Installation Parts Packed With the Faucet

The carbon faucet's connection parts, including the three-way ball valve and an adapter for either common valve size, are in its box. The Viomi V6 PRO, Viomi V8 PRO and Viomi M1 arrive with their cartridges already installed, ready for first use.

Faucets That Show TDS and Filter Life

TDS, short for total dissolved solids, gives the household one number to glance at on a purified-water display. Every display faucet in this comparison shows TDS, together with filter life or a filter-due alert, and anyone in the household who fills a glass sees the same readings, with no phone needed to see the basics. On the Viomi V8 PRO and Viomi V6 PRO, each cartridge also has its own status light, so a quick look while filling a kettle shows which one is coming due and which to have ready, even for someone who never opens the cabinet. The Viomi M1's touchscreen can show tap-water and purified-water TDS side by side.

The PRO faucets also carry a Wi-Fi indicator, and the Viomi app adds water-use patterns and system performance for anyone who wants the longer view. App and alert features beyond the faucet are covered in our comparison of smart water purifier brands by feature.

Pouring is the other job a smart faucet can take on. On the Viomi M1, three preset volumes, including 10 ounces for a glass and 40 ounces for a large bottle, run with one touch.

Picking a Faucet Setup for Your Sink

Keeping the current faucet points to a direct-connect filter, since filtered water comes out of the faucet already on the sink. A second tap, whether the plain faucet of a carbon filter such as the Viomi Under-Sink Carbon Filter, which runs on water pressure alone, or a display faucet on one of the RO systems in the table, suits a kitchen that wants drinking water kept apart from the washing-up faucet. Since that second tap sits beside the main faucet, its look matters along with what it shows: a display faucet adds readings at a glance, and a plain tap keeps the counter simple.

FAQ

How many countertop holes does an under-sink filter with a faucet need?

Each drinking faucet uses one countertop hole, whether it is a plain tap or a display faucet. For a kitchen that would rather keep its current faucet, the Viomi Under-Sink Water Filtration System (VM-IUO1PCW-L-US) connects to it directly, so filtered water comes out of the faucet already on the sink.

Can I use my existing kitchen faucet instead of a new one?

Yes, with a direct-connect filter such as the Viomi Under-Sink Water Filtration System (VM-IUO1PCW-L-US), which feeds the faucet you already have; Waterdrop and Aquasana make direct-connect filters too. With the Viomi direct-connect system, the faucet keeps its look and handle, and the water it pours runs through the same 0.5-micron cartridge used in the dedicated-faucet version. For RO water from that same faucet, Culligan's ClearLink PRO switches it between RO and tap water at the touch of a button.

Does a separate drinking faucet change how the main faucet works?

The main kitchen faucet keeps working exactly as before. The Viomi Under-Sink Carbon Filter takes water from the cold supply through its three-way ball valve, so the main faucet still delivers hot and cold tap water for washing up, and an RO system sends its purified water to its own drinking faucet. The two taps simply sit side by side, one for washing and one for drinking and cooking water, so a pot can be filled with purified water while the sink is full of dishes. Keeping the two apart also saves the purified water for drinking, coffee and cooking, while the washing-up runs on tap water.

What does the NSF/ANSI/CAN 372 mark tell you about a faucet system?

NSF/ANSI/CAN 372 is the standard for lead content in the parts of a product that touch drinking water, so the mark speaks to the materials the water passes through on its way to the glass. Intertek has authorized the mark for the Viomi V6 PRO, Viomi V8 PRO, Viomi B6W and both Viomi under-sink carbon models. Our article on filter brands with NSF/ANSI 372 certification explains how the standard works.

Does a display faucet need its own power supply?

No separate supply is needed at the faucet. The main unit of the Viomi V6 PRO, Viomi V8 PRO and Viomi M1 powers the faucet display through a connecting cable, so the faucet itself needs no batteries or separate power source, and the counter stays free of extra cords. A drinking faucet on a carbon filter works on water pressure alone, so it needs no power at all.