What NSF/ANSI 177 means for a shower filter

Last reviewed 2026-10-16.

NSF/ANSI 177 is the standard for shower filtration systems. It has one claim, free available chlorine reduction. A certified listing names the model, its replacement element, the service cycle in gallons and the flow rate in gallons per minute.

Checked on 2026-10-16 in NSF International listing, NSF/ANSI 177 (https://info.nsf.org/Certified/DWTU/Listings.asp?Standard=177), which lists 7 makers and 11 products. Amazon offers read on 2026-10-16 for a US address.

What a listing contains

• The company and the facility that makes the product.
• The trade name or model, and the replacement element.
• The service cycle: the volume, in gallons, one element is certified for.
• The flow rate, in gallons per minute.
• The claim: free available chlorine reduction.

Free available chlorine is the chlorine that is added to tap water as a disinfectant. Some systems use chloramine; the NSF/ANSI 177 claim on these listings is for free available chlorine.

What it does not cover

NSF/ANSI 177 is an aesthetic-effects standard, like NSF/ANSI 42 for drinking-water filters. It is not a health-effects standard such as NSF/ANSI 53, and a shower filter listing makes no lead, PFAS or other contaminant claim. A note that a product meets NSF/ANSI/CAN 372 is about the lead content of its materials, not about what it removes from water. See NSF/ANSI 42 vs 53 vs 401.

How to check a shower filter

Find the model or trade name, then look for it in the certifier's own listing: NSF's NSF/ANSI 177 listing, IAPMO R&T's directory or WQA's Gold Seal search. A logo or the words "meets NSF 177" on a box or a product page is not the listing. See what "NSF certified" actually means.

Other certifiers of NSF/ANSI 177

NSF International, IAPMO R&T and WQA all certify shower filters to NSF/ANSI 177. Read 2026-10-16: IAPMO R&T's product listing directory shows 14 active NSF/ANSI 177 rows (search by standard). The listees include Culligan International, Kohler Company, Sprite Industries, AquaTru LLC and GE Appliances. (IAPMO R&T directory). WQA's Gold Seal search shows Multipure International (DBA Rainshower) with a shower filter under NSF/ANSI 177, for free available chlorine. (WQA search). These listings are not checked model by model on these pages, and no product from them is linked. A brand missing from NSF's own listing can still be certified to NSF/ANSI 177 by IAPMO R&T or WQA.

Filters on NSF's listing: NSF/ANSI 177 certified shower filters.

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.

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