Choose with confidence

NSF/ANSI certifications, flow rates, grains of hardness and filter life explained in plain numbers.

Drinking-water filters

Point-of-use filters for the kitchen: pitchers, faucet mounts, countertop units and under-sink carbon systems.

ComparisonPitcher vs Under-Sink Water Filter

Pitcher, faucet and under-sink water filters compared on certified reductions, capacity, flow and cost per gallon, with simple running-cost math.

Reverse osmosis

Under-sink tank and tankless RO, countertop RO, remineralization stages and membranes.

Reverse osmosis hub →

ComparisonReverse Osmosis vs Carbon Filter

RO vs carbon

Reverse osmosis vs activated carbon filters: what each removes, wastewater, minerals, installation and running costs, matched to your water test.

Whole-house & softeners

Sediment, carbon and specialty-media systems at the main line, salt-based softeners and salt-free conditioners.

Whole-house & softeners hub →

Buying guideHow to Choose a Whole-House Water Filter

Whole-house filters

Choose a whole-house water filter: match media to the problem, size the flow rate, read micron ratings and plan for iron, sulfur and UV on well water.

Buying guideWater Softener Sizing

Softener sizing

How to size a water softener: convert hardness to grains per gallon, estimate daily use, allow for iron, and pick a capacity that regenerates weekly.

Well water

Iron and manganese filters, sulfur treatment, UV disinfection and well-specific testing.

Well water hub →

Buying guideWell Water Testing

Well testing

Private well testing guide: annual bacteria and nitrate tests, when to test for arsenic, lead and more, how to sample, and how to pick a certified lab.

Testing & parts

Lab test kits, strips, TDS and hardness meters, replacement cartridges and installation parts.

Testing & parts hub →

Buying guideWater Filter Certifications Explained

Certifications

What NSF/ANSI 42, 53, 58, 401, 55 and 44 certify, how to read a certification listing, and why a filter's box claims are not the same as certified claims.