Weddell Duo Shower Filter (WD-100)

1. Proven reduction 35% of the rating 4 of 5

   NSF lists it for free chlorine and Weddell’s test table shows 93% or more through 10,000 gallons; a reviewer’s lab test also saw by-products removed. PFAS is lab-verified, not certified, and chloramine is not covered.

2. What touches the water 20% of the rating 3 of 5

   A plastic housing of unnamed type with plain carbon and sediment media and no metals, silver or fragrance named. NSF evaluated it as lead-free, but there is no wider materials certificate.

3. Independent testing 15% of the rating 4 of 5

   A paid NSF listing with the full test table published, plus a reviewer’s before-and-after lab test with clean results. That test was a single sample, run by a site that earns affiliate income.

4. Trust 10% of the rating 3 of 5

   No Prop 65 notice or recall found, and the test data are public. Against that, skin and hair claims cite no study, and Weddell pays commissions to affiliates and to health workers it features as “Wellness Experts”.

5. Running cost & value 20% of the rating 5 of 5

   $80 plus about $25 per cartridge pair every 5 to 6 months: roughly $330 to $440 over five years. The Sprite Slim-Line 2 costs about $230 over the same time.

The rating, 3.9 of 5, is the weighted average of these scores. See how we rank water filters and our standard.

• Amazon (opens in a new tab) approx. $90. Black, model WD-100BL, the model name NSF’s listing gives for the black color. Shipped by Amazon and sold by WeddellWater, the brand’s own Amazon store. The listing does not say whether it is the original or the redesigned housing; the white and pink versions have their own pages (pink: B0DJJQQG5J).

Prices as we saw them on October 23, 2026. They change often. These links carry no tracking code and earn us nothing.

1. Two cartridges in a plastic housing: a sediment filter and an activated carbon block. Weddell does not name the plastic or the carbon source; Amazon’s listing gives the housing material as ABS
2. Weddell’s pages name no copper-zinc alloy, calcium sulfite, silver or fragrance
3. NSF also evaluated the product as lead-free (weighted lead content of 0.25% or less), and Weddell lists NSF/ANSI/CAN 372
4. The redesigned housing adds stainless steel reinforcement at the top and bottom (Weddell)
5. Plumber’s tape for the threads is in the box (Weddell’s page); Amazon’s listing for the black Duo calls it Teflon tape, which is PTFE, a fluoropolymer. Weddell does not name the tape’s material

• Paid certification NSF International May 2026

  Lists the Weddell Duo (WD-100, element WD-100F) under NSF/ANSI 177 for free available chlorine reduction: 8,000 gallons at 2.8 gpm, made in Korea, with a lead-free evaluation. The snapshot we read is dated 2026-05-10. NSF is paid by the maker for the listing. Open ↗ (opens in a new tab)

• Paid certification NSF/ANSI 177 test, table published by Weddell November 2023

  Chlorine reduction from 2.0 mg/L, test completed 2023-11-21: 97.4% or more at 4,200 gallons, 95.5% at 8,000 and 93.3% at 10,000, against the standard’s 50% minimum. Both Duo versions are said to be covered by an April 2026 recertification. Open ↗ (opens in a new tab)

• Maker’s own test IAPMO R&T lab, commissioned by Weddell September 2023

  A 2023 total PFAS test run to the NSF/ANSI 53 method at 2.8 gpm: reduction of at least 99.05%, marked pass. The run covered 2,500 gallons (5,000 gallons at 200%), not the 8,000 to 10,000-gallon chlorine rating. Weddell also publishes a 2023 NSF/ANSI 42 particulate test (Class IV, at least 96.59%). It calls these “verified”, not certified, and NSF’s listing names free chlorine only. Open ↗ (opens in a new tab)

• Independent Water Filter Guru (earns affiliate income; lab kits from Tap Score by SimpleLab) July 2026

  One before-and-after test in a Colorado home: chlorine 1.68 ppm to 0 and four disinfection by-products (chloroform 5.47 ppb and three others) to 0. Hardness did not change (2%). It did not test microplastics, and the reviewer says it has no firsthand data on hot-water performance. Open ↗ (opens in a new tab)

Is it clinically proven for skin and hair?

We could not find the study. Weddell’s page says “clinically tested” and “dermatologist approved” without naming a trial, a sponsor or a dermatologist (Weddell (opens in a new tab)). Our shower filter guide found no trial of any shower filter on skin or hair, so treat this as a comfort choice.

Who gets paid when people recommend it?

Weddell’s “Wellness Experts” page offers healthcare workers commissions, discount codes, free filters and a feature on its site for recommending the filter, and its pages list nurses and physician assistants as experts (Weddell (opens in a new tab)). New affiliate sign-ups are paused (Weddell (opens in a new tab)). The reviewer we cite, Water Filter Guru, also earns affiliate commissions on its links.

Does carbon still work in hot shower water?

The NSF test is the one run at shower-style conditions, and Weddell’s table shows it passing through 10,000 gallons. In its Sprite review the same reviewer says it tests shower filters with cold water, so its 100% result is likely a best case. A reader asked the reviewer the same question; the reviewer called it speculation and had no data (comment thread (opens in a new tab)).

Does the plastic shed microplastics?

Weddell says the filter reduces microplastics, but the reviewer did not test for them and Weddell has no materials-safety certificate beyond the lead-free evaluation (review (opens in a new tab)). We treat both as unverified.

Is there PTFE (Teflon) in the box?

Weddell’s page lists “plumber’s tape” in the box and tells you to wrap the threads with it, and Amazon’s listing for the black Duo calls it Teflon tape (Amazon (opens in a new tab)). Teflon is PTFE, a fluoropolymer. The tape seals the connection and is not part of the filter, Weddell does not name its material, and we found no test of it. If you want to avoid PTFE, ask Weddell what the tape is made of before you buy.

Any recalls, lawsuits or Prop 65 notices?

None found. California’s Prop 65 notice search shows no notice naming Weddell, and the federal product-recall database has no Weddell entry (both checked 2026-10-23).

• NSF International’s own directory lists the Weddell Duo (WD-100, element WD-100F) under NSF/ANSI 177 for free available chlorine reduction, at 8,000 gallons and 2.8 gpm, and notes the housing was evaluated as lead-free. Weddell says both versions were recertified in April 2026.
• Weddell publishes the NSF test table: from 2.0 mg/L of chlorine, the filter cut at least 93% through the full 10,000-gallon test (95.5% at 8,000 gallons, 93.3% at 10,000).
• A reviewer, Water Filter Guru, ran before-and-after lab tests in a Colorado home: chlorine fell from 1.68 ppm to 0 and all four disinfection by-products it found (chloroform, bromodichloromethane, dibromochloromethane and bromochloromethane) fell to 0. It was one of only two of the more than a dozen shower filters that reviewer tested to remove by-products.
• The media are plain: a sediment filter and an activated carbon block. Weddell’s pages name no copper-zinc alloy, calcium sulfite, silver or fragrance.
• Replacement cartridge pairs cost $24.99 (sediment plus carbon), changed every 5 to 6 months or when pressure drops, so about $330 to $440 over five years with the unit.

• The skin, scalp and hair claims have no named study behind them. Weddell calls the filter “clinically tested” and “dermatologist approved” but names no trial, sponsor or dermatologist, and we found no published trial. Our guide found no trial of any shower filter on skin or hair.
• It is certified for free chlorine only. It does not reduce chloramine. The PFAS result on Weddell’s page is a lab verification (a test, not a certificate), and the by-product result is one reviewer’s single sample.
• The capacity is unclear. NSF’s listing says 8,000 gallons; Weddell’s newer pages say 10,000 for both versions. We could not see the April 2026 recertification in the NSF snapshot we read.
• The housing is plastic (Weddell does not name it) and there is no materials-safety certificate beyond the lead-free evaluation. The original and redesigned cartridges are not interchangeable.
• Water Filter Guru reads Weddell’s returns policy as a 30-day window with a 10% restocking fee that appears to apply even to a defective unit.

Third-party tested

Yes

Tested by

NSF International, paid for by the maker

1. Weddell Duo Shower Filter: Weddell product page. Maker’s page. Shows $79.99 (marked down from $89.99) for the original Duo; the redesigned Duo is $89.99. Cartridge prices from the same store, 2026-10-23. Open ↗ (opens in a new tab)
2. Weddell Water: third-party test reports. Test report. Published by Weddell. The NSF/ANSI 177 chlorine table and the IAPMO lab PFAS table. Open ↗ (opens in a new tab)
3. Weddell: original versus redesigned Duo. Maker’s page. Says both versions are covered by an April 2026 NSF recertification and rated 10,000 gallons. Open ↗ (opens in a new tab)
4. NSF International: NSF/ANSI 177 listings (archived 2026-05-10). Certifier or regulator listing. Weddell Water entry: Weddell Duo WD-100, element WD-100F, 8,000 gallons, 2.8 gpm, free available chlorine reduction, lead-free evaluation. Open ↗ (opens in a new tab)
5. Water Filter Guru: Weddell Duo shower filter review. Independent source. A reviewer that earns affiliate income. Before-and-after lab tests, flow and cost figures. Open ↗ (opens in a new tab)
6. Water Filter Guru: best shower filters, tested. Independent source. Compares more than a dozen shower filters, including Sprite and AquaTru, on chlorine, by-products and hardness. Open ↗ (opens in a new tab)
7. Weddell Wellness Experts program. Maker’s page. Describes the commissions and free products offered to health workers. Open ↗ (opens in a new tab)
8. Weddell affiliate program page. Maker’s page. Says new affiliate applications are paused during a platform change. Open ↗ (opens in a new tab)

• Do Shower Filters Work? Article Shower filters can cut chlorine, but no trial shows they improve skin or hair. What they do, what hard water does, and where the evidence stops.
• Disinfection Byproducts and Health Risks Article How chlorination protects against pathogens but generates trihalomethanes and other byproducts linked to bladder cancer, reproductive harm, and skin disruption — and what to do about it
• What's in Your Water Article Common contaminants found in US tap water and why they matter for your health