Evidence before endorsements.
WaterFilterList is an independent reference directory for U.S. household water filters and their replacement cartridges. We organize documentation. We do not test water, certify products or rank safety.
The combination is the unit of evidence.
We record the manufacturer, complete system model, complete list of exact replacement elements, certifier, standard, individual reduction claims, capacity, service flow, replacement schedule, source and review date. A family placeholder is kept only when the manufacturer explicitly defines it. Color variants are not counted as separate systems. Retail names are secondary to model numbers.
Two kinds of evidence, clearly labeled.
Registry checked: an accessible official certifier entry was reviewed. Manufacturer document: the manufacturer’s performance sheet identifies the models, cartridges, claims and certification body; we have not independently checked that registry. Certification to an NSF/ANSI standard does not necessarily mean NSF is the certifier. WQA and IAPMO can certify to those standards too.
Document reviews are dated and identify the reviewer. The initial review was performed by Codex against the archived original documents; it is not a claim of third-party human inspection. Original sources remain linked so that users and maintainers can inspect the scope.
A standard is not a blanket claim.
- NSF/ANSI 42: specific aesthetic claims, such as chlorine taste and odor.
- NSF/ANSI 53: specific health-related reduction claims. Lead is not implied unless it is listed.
- NSF/ANSI 58: reverse osmosis systems and individually listed reduction claims.
- NSF/ANSI 401: specific emerging compounds and incidental contaminants. We preserve model-specific footnotes.
- NSF/ANSI/CAN 61: health-effects requirements for drinking-water system components, not a blanket treatment claim.
- NSF/ANSI/CAN 372: lead content of product materials. It does not establish removal of lead from water.
These descriptions summarize the standards named in our linked source documents. We never convert a materials-only record into a reduction claim. A “total PFAS” entry means the defined test mixture in that source, not every PFAS compound.
Absence is not evidence of absence.
“Not verified here” means our catalog has no reviewed record for that claim or combination. It does not mean a product is uncertified. We do not infer claims from brand reputation, a logo, cartridge fit or another system’s results.
Cost with the assumptions visible.
Our calculator budgets for an ongoing full year, separately for every replacement item in a multi-stage configuration. Pack prices are divided by the number of usable replacement units; a kit is one complete replacement kit. A total is withheld when any item lacks a price or schedule. It uses the earlier capacity or time limit, rounds cartridge consumption up to whole units and multiplies by the per-cartridge price. Initial supplied cartridges are not deducted. Tax, shipping, installation, electricity and water are excluded. Unknown prices stay blank until you supply a price; an unknown interval is explicitly labeled as incomplete.
Responsible source access & updates.
We use manufacturer documents and publicly accessible, permitted records. We do not bypass paywalls, CAPTCHAs, access restrictions or registry limits. When a listing cannot be accessed, a maintainer can import authorized CSV data and inspect the original source manually. Imports remain pending until an explicit reviewer and verification note are recorded.
Review certification evidence at least every 90 days and prices every 30 days, or sooner after a source change. Confirm model lists, footnotes, source revision and cartridge identifiers before approval. Withdraw outdated combinations rather than broadening their claims. The catalog includes legacy models to support cartridge matching; retail availability is not checked.
Found a discrepancy? Compare the linked source and your model label before relying on the entry. View all sources and review dates →