Comparison of NSF certifications and tests of major gravity filters
| Brand / Filter | NSF 42 certified (aesthetic contaminants) |
NSF 42 tested (lab) |
NSF 53 tested (lab) |
NSF P231 tested (independent lab) |
Duration (2 filters) | Price / year (≈) |
|---|---|---|---|---|---|---|
| Black Filters (activated carbon) | ✔️ Yes (performance included) | ❌ No | ❌ No | ❌ No | ≈ 12 months | ≈ 60–90€ |
| Doulton Ultra Sterasyl | ✔️ Yes (performance included) | ✔️ Yes | ✔️ Yes (depending on model) | ❌ No | ≈ 6 months | ≈ 120–160€ |
| British Berkefeld Ultra Fluoride | ✔️ Yes (performance included) | ✔️ Yes | ✔️ Yes | ❌ No | ≈ 6 months | ≈ 140–180€ |
| Imperial Gravity Filters AMB | ✔️ Yes (performance included, depending on original technology)** | ✔️ Yes (Envirotek) | ✔️ Yes (Envirotek) | ⚠️ Variable | ≈ 12 months | ≈ 90–110€ |
| Multipure | ✔️ Yes (performance included) | ✔️ Yes | ✔️ Yes | ❌ No | ≈ 12 months | ≈ 120–150€ |
| ZeroWater | ✔️ Yes (performance included) | ✔️ Yes | ✔️ Yes | ❌ No | ≈ 1–2 months | ≈ 200–300€ |
| Brita | ✔️ Yes (performance included) | ✔️ Yes | ✔️ Yes | ❌ No | ≈ 1 month | ≈ 180–250€ |
| ProOne G2.0 | ⚠️ Yes (materials only) | ✔️ Yes (Envirotek) | ✔️ Yes (Envirotek) | ✔️ Yes (Envirotek) | ≈ 6 months | ≈ 140–180€ |
| Propur (formerly ProOne) | ⚠️ Yes (materials only) | ✔️ Yes (Envirotek) | ✔️ Yes (Envirotek) | ✔️ Yes (Envirotek) | ≈ 6 months | ≈ 140–180€ |
| Phoenix Gravity Filters | ⚠️ Ongoing | ✔️ Yes | ✔️ Yes | ✔️ Yes | ≈ 12 months | ≈ 110–140€ |
| Coldstream FTO+ (CF163W) | ❌ No* | ✔️ Yes (IAPMO / Envirotek) | ✔️ Yes (IAPMO / Envirotek) | ✔️ Yes (IAPMO / Envirotek) | ≈ 6 months | ≈ 160–180€ |
| Black Berkey | ❌ No | ✔️ Yes (Envirotek) | ✔️ Yes (Envirotek) | ✔️ Yes (ASI) | ≈ 36 months | ≈ 70–90€ |
| Purewell | ❌ No | ⚠️ Variable | ⚠️ Variable | ⚠️ Variable | ≈ 12 months | ≈ 40–70€ |
| Weeplow | ❌ No | ⚠️ Variable | ⚠️ Variable | ⚠️ Variable | ≈ 12 months | ≈ 80–100€ |
* Case of the Coldstream FTO+ (CF163W): unlike some presentations published in online comparisons, NSF certification cannot be granted “by proxy.” It applies only to products specifically referenced in the official NSF.org database.
Important: annual prices are average estimates based on observed rates and replacement frequency. They may vary depending on usage and distributors.
