Methodology
How we talk about certifications, softening vs filtration, and why we refuse to invent health or performance claims.
How we cite NSF, WQA, and IAPMO
When we discuss a product’s certification or a claimed contaminant reduction, we treat the official listing as the source of truth—not marketing copy, retailer bullets, or third-party blogs.
- NSF International — listings for drinking water treatment units (DWTU) and related standards
- Water Quality Association (WQA) — Gold Seal and related certification programs
- IAPMO — product certification and related listings where applicable
We cite the standard number (for example, NSF/ANSI 44), the claim scope shown on the listing, and—when we discuss a specific model—encourage readers to verify the current listing themselves.
Official lookup (NSF DWTU)
Use NSF’s public drinking water treatment unit listings to confirm what a model is certified for:
NSF Certified Drinking Water Treatment Units lookup
Listings change. Always check the current entry for model number, standard, and claim.
Softening vs filtration (do not mix them up)
Water softeners (hardness)
Ion-exchange (salt-based) softeners are commonly evaluated under NSF/ANSI 44 for residential cation exchange water softeners. That standard addresses softening performance related to hardness reduction (among other listing requirements)—not a catch-all for every drinking-water contaminant.
Salt-free “conditioners” or “descalers” are not softeners under NSF/ANSI 44. See Salt vs Salt-Free.
Filtration / treatment claims
Contaminant reduction claims belong only where a listing supports them under the relevant standard (for example, various NSF/ANSI drinking water treatment standards). We do not extend a softener listing into filtration health claims, or the reverse.
What we never invent
- We never invent health outcomes, disease-prevention claims, or medical advice.
- We never invent contaminant-removal percentages, “removes everything,” or filtration-performance numbers.
- We never invent NSF/ANSI, WQA, or IAPMO certifications or claim scopes.
- We never treat marketing phrases (“salt-free softener,” “medical grade,” “detox”) as certification evidence.
- If a claim is not on an NSF, WQA, or IAPMO listing (or equivalent published listing we cite), we do not present it as certified fact.
How comparisons will work
When product comparisons go live, our approach is:
- State the decision criteria (e.g., hardness reduction vs conditioning, maintenance, TCO, listing status).
- Separate category education from model-specific claims.
- Point to official listings for any certification-dependent statement.
- Disclose affiliate relationships clearly (FTC-ready) when affiliate links are used.
We are not a coupon site and we do not publish thin “Top 10” rankings divorced from criteria and listings.
Limitations
- Your water chemistry varies. Municipal Consumer Confidence Reports and private well lab tests matter more than generic averages.
- Installation, plumbing codes, and local water utility rules are outside our control.
- Listings and models change; verify before you buy.