# About Water Filter Nerd

# About Water Filter Nerd

**strong** A pitcher, an under sink system, and a whole house filter all make the same promise. Few can prove it. We start at the NSF listing and work outward.

**strong**: certified removal scope, certification and test transparency, filter life, cost per gallon, flow rate, install and footprint, and maintenance burden. The result is the Nerd Stamp™, a 1 to 7 rating with a public [methodology](/methodology).

**strong** No lab, no borrowed units, no sample bottles. Every review is a spec breakdown built from manufacturer documentation, NSF and WQA certification records, and published third party performance reports, held against the claims on the box. When a maker will not publish a certification number, the review says so and the score reflects it.

**strong** The site is funded by Amazon affiliate commissions, disclosed on every page and in full at our [affiliate disclosure](/affiliate-disclosure). A filter cannot buy its score. A brand cannot buy its position.

**strong** if a published specification is wrong, we correct it and update the revision date on the page. Specifications are sourced from manufacturer documentation, NSF and WQA certification listings, and published performance reports.