Drinking Water Filtration

Reverse osmosis systems, under-sink filters, and countertop options for hard water homes that want clean, great-tasting drinking water.

Note on water softeners and drinking water: A salt-based water softener makes water softer but replaces calcium and magnesium with small amounts of sodium. If you have a water softener, many households add a point-of-use RO filter for drinking water to remove the sodium.

Is Hard Water Safe to Drink?

Yes. Hard water is not a health risk. The calcium and magnesium in hard water are the same minerals found in dietary supplements. The World Health Organization notes that hard water may even provide a small portion of daily mineral intake. However, very hard water has a chalk-like taste many people dislike, and scaling in kettles and coffee makers is a real inconvenience.

Filtration Options by Budget

Pitcher Filter ($25 to $60)

Brita and ZeroWater pitchers. ZeroWater removes virtually all dissolved solids including hardness minerals but filters need frequent replacement in hard water. Brita reduces chlorine taste but leaves most minerals.

Countertop Filter ($80 to $200)

No installation required, good for renters. Berkey and similar gravity systems are popular. Check NSF certification for the contaminants you care about.

Under-Sink Filter ($150 to $400)

Installed under the kitchen sink with a dedicated tap. Reduces a wide range of contaminants. Does not always remove hardness minerals unless it uses RO membranes.

Reverse Osmosis ($200 to $850)

The most thorough option. Removes 99%+ of contaminants including hardness minerals, lead, fluoride, PFAS, and nitrates. Produces some wastewater. The iSpring RCC7AK is our top pick.

Our Top Picks

Best Overall RO System

iSpring RCC7AK 6-Stage RO System

★★★★★ 4.6/5 - top pick in our 2026 RO system review

6-stage filtration with alkaline remineralization stage. Removes 99%+ of contaminants including PFAS, lead, and fluoride. Restores beneficial minerals for better taste.

Pros

  • 99%+ contaminant removal
  • Alkaline stage improves taste
  • Easy filter replacement
  • Widely available, good support
  • Proven 10+ year track record

Cons

  • Requires under-sink space
  • Wastes some water (3:1 ratio)
  • Tank takes 2 to 4 hours to refill
  • Annual filter cost ~$60
Check Price on Amazon Read Full RO Guide Price changes frequently. Check Amazon for current pricing.

Drinking Water Guides