Do I need a whole house water filter? Point-of-use at the sink or the main line

One tap or the whole house at a glance

The practical difference between one tap and the whole house

As read on October 14, 2026, Waterdrop's WHF3T-PG whole-house filter was $369.99 and connects to the main water line, and its only certification is NSF/ANSI 372 for lead-free materials. A point-of-use system treats the water at one tap, for drinking and cooking; a whole-house filter treats the water entering the home.

On Waterdrop's pages, NSF/ANSI 42, 53 and 58 lines appear on its under-sink filters and RO systems, while its whole-house filters list NSF/ANSI 372 only. So start from what your water report names and where you need the water treated.

Point of use: under the sink or on the counter

Waterdrop's Direct Connect WD-10UA, $58.99, goes on the cold line under the sink and lists NSF/ANSI 42 and 372. The G3P600 tankless RO system, $539.00, needs an outlet and a drain line, and Waterdrop says IAPMO R&T certified it against NSF/ANSI 58 for the claims on its Performance Data Sheet. Countertop RO such as the K19-SFK, $349.00, needs no plumbing.

Whole house: on the main water line

The WHF3T-PG is rated 15 GPM. Waterdrop's WHF2E-FC page says it fits standard 1-inch FNPT inlet and outlet connections and that each filter provides up to 50,000 gallons or 6 months, and the WHF3T-FG, $419.99, is Waterdrop's model for iron and manganese.

Waterdrop's extended-warranty terms say well water needs pre-filtration; its BG100 is a reusable 5 micron spin-down sediment filter rated 20 gpm, at $169.99. The Waterdrop whole-house guide covers each model.

Start from the report or a well test

Your utility's Consumer Confidence Report, due each year by July 1, lists the regulated contaminants found in its water; if you did not get one, EPA's CCR search tool can find it. For a private well, EPA advises testing every year for coliform bacteria, nitrates, total dissolved solids and pH, through a laboratory certified for drinking water.