We take our rankings seriously, so here’s exactly how we evaluate whole-house water filters: what we check, what we don’t do, and how we keep the whole thing honest.
What we check
- Manufacturer specifications: we read the spec sheets and installation manuals, not just the marketing pages, checking flow rate, media, capacity, warranty, and maintenance requirements.
- Third-party certifications: we check the NSF and WQA certification databases, and we distinguish system-level certification from component-only certification.
- Total cost of ownership: purchase price plus replacement filters and media, salt, and years of maintenance, calculated over 10 years. The sticker price rarely tells the whole story.
- Water-type suitability: city water and well water get different picks. We match the system to the water problem instead of recommending one-size-fits-all.
- Editorial independence: manufacturers cannot pay for rankings, and affiliate commissions never change our picks.
What we check for every product
Every product we review goes through the same research checklist:
- Research checked: September 2026
- Manufacturer specifications
- Installation manual
- NSF certification database
- WQA certification database
- Warranty terms
- Replacement media pricing
What we don’t do
We don’t own a test lab, and we don’t pretend to. We don’t claim to have lab-tested systems we haven’t tested. When a performance claim comes from a manufacturer, we identify it as such. And if a brand blurs the line, we say so.
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