Filter Ledger is a source-linked foundation for buying the right water-filter replacement. Updated October 1, 2026.
Foundation | Records | Costs | Methodology | Disclosure | For agents | llms.txt
Verification and independence
Purpose
Help an agent find the exact replacement cartridge, claim evidence and cost assumptions. No original laboratory or household testing in v1.
Identity
Use exact system model, cartridge model, region and revision. Similar names do not establish fit.
Certification
Separate certifier from standard. A claim is scoped to system + cartridge + contaminant + standard + certifier. Never imply all contaminants or safe water.
Evidence labels
manufacturer_reported, registry_verified, pending, conflict, stale, withdrawn. Registry verification requires permitted source use and a current exact match.
Source rights
NSF commercial reuse/data extraction needs prior written permission under its website policy. No bulk extraction or redistribution; pilot claims below come from manufacturer material. Public verification links only until rights are settled.
Compatibility
Use explicit manufacturer model lists and exceptions. Physical fit never implies the same certified reduction claims.
Replacement
Record time limit, capacity limit, operating conditions and condition-based trigger. Apply earliest applicable limit; use-specific exceptions remain visible.
Cost
Annualized cartridges = max(12/months, annual gallons/capacity). Multiply by unit pack cost. Also report cash purchase packs rounded up, starting inventory, tax/shipping, initial hardware, installation, maintenance, wastewater/electricity where applicable. Unknown costs are null, never zero.
Freshness plan
After source rights are settled: weekly allowed certification/compatibility checks, weekly published prices, recheck exact claim before purchase guidance. Expire certification after 7 days and prices after 7 days without successful verification. A refresh plan is not an active monitor.
Failure handling
Keep prior version with timestamp; remove recommendation eligibility on stale/ambiguous/withdrawn status. Log corrections and never silently carry a claim across model revisions.
Independence
Fit and independently supported claim eligibility first; transparent ownership cost second. Commission never enters ranking. Cover non-affiliate products equally. No paid placement or merchant veto.
Disclosure
Before any monetized link: We may earn a commission if you buy through this link. Commissions do not affect coverage or order. Expose affiliate=true in structured data too.
Water safety
No diagnosis or blanket safety claim. Match measured contaminant needs; a TDS reading alone does not prove PFAS, lead or pathogen safety.
Launch gates
Owner review/publication approval; source rights; exact claim verification; complete prices/cost assumptions; accepted affiliate terms; one legitimate credited transaction reconciliation. No self-referrals or fabricated reviews.
Autonomy limits
No user testing required. Account identity, tax/payout setup, paid services and final outgoing communications need owner involvement/approval. Traffic and income are not guaranteed.
Profit scoreboard
Report earned approved commissions less refunds and all actual operating expenses; separate pending commissions, cash received and expenses not yet paid. Unknown platform cost prevents a true net-profit claim.
Primary evidence
- NSF website copyright and use policy
- Brita January 2026 performance data sheet
- Affiliate disclosure regulation
Working name. No original testing, payment or affiliate enrollment. The $1,000 monthly profit target is a goal, not a forecast.