Refrigerator Water Filters Ranked by Cost per Certified Gallon

Last reviewed July 2026.

Every refrigerator water filter we track that holds an accredited certification, ranked on cost per gallon of certified filtration — the filter's price divided by the capacity its certification actually covers. Sticker price tells you almost nothing: the cheapest filter here is Waterdrop WDS-F27 at $0.030/gallon, and the most expensive, everydrop (Whirlpool) EDR1RXD1, costs 10.0× more for every gallon it filters.

Price per filter ÷ certified capacity in gallons. Prices carry the date they were checked in the dataset and drift; the retailer page is authoritative.

Certified, but not yet rankable

• everydrop (Whirlpool) EDR2RXD1 — price pending.
• Samsung DA29-00020B — price pending.
• Waterdrop WD-F38 — no rated capacity published.

Read the standards before the price

A cheap cost per gallon means nothing if the certification doesn't cover the contaminant you're worried about. NSF/ANSI 42 is chlorine, taste and odour — not a health claim. 53 is where lead lives. 401 covers PFAS and pharmaceuticals. Sort by the columns above and check the ✓ before the dollar figure — see 42 vs 53 vs 401.

We do not test filters — we index what accredited certifiers publish, with attribution, and make no health or treatment claims. A certification covers a specific model against a specific standard; it is not a general seal of quality. We are not affiliated with NSF International.