Waterdrop vs Samsung: which is actually certified — and what does a certified gallon cost?

Last reviewed July 2026.

Same job, same shelf — but the certifications underneath are not the same. Here is Waterdrop against Samsung on the only two axes we score: what the certification actually covers, and what a certified gallon costs.

• Waterdrop: cheapest certified-for-lead filter is the WDS-F27 at $0.030/certified gallon (NSF, NSF/ANSI 42, 53).
• Samsung: holds NSF/ANSI 53 (lead), price pending — not yet rankable.

Every model, side by side

Price per filter ÷ certified capacity in gallons. Certification data from the certifiers' public listings; the listing always wins.

How often you actually replace them

On this pair the replacement interval is a wash: both are certified for 300 gallons, so neither brand buys you a longer run between cartridges. At roughly half a gallon of drinking water per person per day that is 20 months for one person, or 5 months for a family of four — the same either way.

That is worth knowing because it removes a variable. With capacity equal, the comparison really is just what a covered gallon costs and which standards each listing names — there is no hidden convenience argument pulling the other way. The certified claim still only holds within that rated capacity: run either one long past its gallons and the lead or PFOA/PFOS claim stops applying, even though the filter still passes water.

So which one

On cost per certified gallon there is only one rankable answer here: Waterdrop. The WDS-F27 holds NSF/ANSI 53 with NSF and works out at $0.030 per certified gallon. It is the only side of this comparison where a lead claim is both listed and priceable.

Samsung does hold a real NSF/ANSI 53 listing — this is not a certification failure — but we have no reliable current price for a replacement cartridge, so it cannot be put on the same cost-per-certified-gallon axis. If price is the only thing between them, check what a cartridge costs today and do the division yourself: price per filter ÷ certified gallons.

None of which counts against Samsung's lead claim itself — it is listed and real. It is the price we cannot stand behind, not the certification. If lead is not your concern, the comparison above is the wrong one to be reading; start from the full ranking and pick on the claim you actually want.

The full stories: Is Waterdrop NSF certified? · Is Samsung NSF certified? · what 42, 53 and 401 mean

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.