At Norde, transparency is foundational. Our products undergo NSF certification where applicable and are independently tested by accredited laboratories to verify performance across key water quality metrics. This page shares our third-party test data and product specifications — so you can see exactly how each Norde product performs.
Performance Data for the Duo Filter+
Contaminants
While Norde products are designed to address a wide range of water quality concerns, we only publish reduction claims for contaminants that have been tested according to established industry standards. Third-party testing is extensive and ongoing, and we prioritise contaminants most relevant to shower water exposure. As additional testing is completed, this information will be updated accordingly.
Chlorine
The Duo Filter+ was certified by NSF International to NSF/ANSI 177 and NSF/ANSI/CAN 372 standards in 2023.
| NSF/ANSI 177 | Test Completed | Minimum Reduction | Maximum Reduction | Results |
|---|---|---|---|---|
| Chlorine Reduction | 11/21/2023 | ≥87% | ≥99% | PASS |
Data Analysis Table
| Sample Point | Inf. Average (mg/L) | Avg. Effluent 1 (mg/L) | Avg. Effluent 2 (mg/L) | Eff. % Reduction 1 | Eff. % Reduction 2 | Avg. % Reduction |
|---|---|---|---|---|---|---|
| 3,200 gallons (40% capacity) | 2.1 | 0.08 | 0.07 | 91.0 | 93.0 | 96.4 |
| 4,000 gallons (50% capacity) | 2.1 | 0.08 | 0.07 | 91.0 | 93.0 | 96.4 |
| 4,800 gallons (60% capacity) | 2.1 | 0.08 | 0.07 | 91.0 | 93.0 | 96.4 |
| 5,600 gallons (70% capacity) | 2.1 | 0.08 | 0.07 | 91.0 | 93.0 | 96.4 |
| 6,400 gallons (80% capacity) | 2.1 | 0.08 | 0.07 | 91.0 | 93.0 | 96.4 |
| 7,200 gallons (90% capacity) | 2.1 | 0.08 | 0.07 | 91.0 | 93.0 | 96.4 |
| 8,000 gallons (100% capacity) | 2.1 | 0.08 | 0.07 | 91.0 | 93.0 | 96.4 |
PFAS
The Duo Filter+ was verified by accredited IAPMO R&T Lab to the NSF/ANSI 53 standard in 2023.
Note: During testing, the flow rate was increased to 2.8 gpm, making the test more challenging to pass, as the NSF/ANSI 53 standard is designed for drinking water, which has a lower flow rate.
| NSF/ANSI 53 | Test Completed | Minimum Reduction | Maximum Reduction | Results |
|---|---|---|---|---|
| PFAS Reduction | 09/23/2023 | ≥99.05% | ≤99.99% | PASS |
Total PFAS Data Summary — Filter 1
| Sample Point | Accumulated Volume (Effluent 1) | Influent 1 PFAS (mg/L) | Effluent 1 PFAS Concentration (mg/L) | Passing Criteria |
|---|---|---|---|---|
| 10 UV | 10 UV | 0.17 | 0.01 | PASSED |
| 50% | 1,200 gallons | 0.10 | 0.02 | PASSED |
| 100% | 2,500 gallons | 0.15 | 0.01 | PASSED |
| 150% | 3,750 gallons | 0.17 | 0.01 | PASSED |
| 180% | 4,500 gallons | 2.19 | ≤0.01 | PASSED |
| 200% | 5,000 gallons | 0.17 | 0.01 | PASSED |
Total PFAS Data Summary — Filter 2
| Sample Point | Accumulated Volume (Effluent 2) | Influent 2 PFAS (mg/L) | Effluent 2 PFAS Concentration (mg/L) | Passing Criteria |
|---|---|---|---|---|
| 10 UV | 10 UV | 0.17 | 0.01 | PASSED |
| 50% | 1,200 gallons | 0.10 | 0.01 | PASSED |
| 100% | 2,500 gallons | 0.15 | 0.01 | PASSED |
| 150% | 3,750 gallons | 0.17 | 0.01 | PASSED |
| 180% | 4,500 gallons | 2.19 | ≤0.01 | PASSED |
| 200% | 5,000 gallons | 0.17 | 0.01 | PASSED |
Particulates
The Duo Filter+ was verified by accredited IAPMO R&T Lab to the NSF/ANSI 42 standard in 2023.
Note: During testing, the samples were evaluated for nominal particulate reduction as a Class IV according to NSF/ANSI 42 section 7.4.1. The flow rate was increased to 2.0 gpm, making the test more challenging to pass, as the NSF/ANSI 42 standard is designed for drinking water, which has a lower flow rate.
| NSF/ANSI 42 | Test Completed | Minimum Reduction | Maximum Reduction | Results |
|---|---|---|---|---|
| Particulate Reduction | 11/28/2023 | ≥96.59% | ≤99.66% | PASS |
Average Influent and Effluent Particle Counts (sizes 15–30 µm)
| Sample Point | Inf. (particles/mL) | E1 (particles/mL) | E2 (particles/mL) | % Reduction E1 | % Reduction E2 |
|---|---|---|---|---|---|
| 2-UV | 11,733 | 133 | 400 | 98.86% | 96.59% |
| Cycle 4 | 21,867 | 67 | 533 | 99.70% | 97.56% |
| 50% Flow | 19,400 | 0 | 67 | 100.00% | 99.66% |
See the results for yourself
Every claim on this page is backed by an independent, accredited laboratory — not a marketing team. The Duo Filter+ removes 99% of chlorine, 99% of PFAS and 99% of particulates before the water reaches your skin and hair.
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