NSF/ANSI 177: Shower filters
Taste, odor and chlorine · Official title: Shower Filtration Systems - Aesthetic Effects
Covers shower filters that attach in front of the showerhead. NSF says they are certified to reduce only free available chlorine.
What it can cover
- Free available chlorine in shower water (listing claim: "Free Available Chlorine Reduction")
What it does not
- Chloramine
- Lead, PFAS or any other health-related contaminant
- Drinking water
The usual mistake
Treating a certified shower filter as a health filter. NSF/ANSI 177 is an aesthetic standard that covers free chlorine only.
The fine print
- WQA listings word the claim as "Free Available Chlorine."
Claims to look for
| Contaminant | Claim on the listing |
|---|---|
| Chlorine |
|
Sources
- NSF Standards for Water Treatment Systems, NSF. Checked Oct. 4, 2026.
- Search for NSF Certified Drinking Water Treatment Units (standards and reduction claims lists), NSF. Checked Oct. 4, 2026.
- Find WQA Certified Products (Gold Seal listings by standard and claim), Water Quality Association. Checked Oct. 4, 2026.