Methodology

How we scout home water systems

Updated September 17, 2026

Filter Scout guides buyers — we don’t wander. “Top rated” on this site means ranked against the criteria below, using brand-published specs and third-party certifications. We do not run a secret lab or invent star ratings.

1. Certifications

We prefer systems with clear NSF/ANSI, IAPMO, or WQA listings for relevant standards (e.g. 42, 53, 58, 401, P473). “Independently tested” without a listing is labeled as such — not equated with certification.

2. Contaminant targets

We map claims to common buyer concerns: PFAS (PFOA/PFOS), lead, chlorine/chloramine, fluoride, VOCs, microplastics. Your local Consumer Confidence Report should drive the shortlist.

3. Cost of ownership

Replacement filters, membrane life, wastewater (RO), and shipping for kits. We flag when sticker price hides multi-year spend — AOV honesty without publishing affiliate economics.

4. Install reality

Countertop plug-in, under-sink DIY, dedicated faucet drilling, or whole-house professional install. Renters and homeowners get different default recommendations.

5. Segment fit

Whole-house is not a drinking-water RO. Pitchers are not tankless under-sink systems. We refuse category confusion in headlines.

6. What we don’t do

No fabricated “we tested 47 filters in our lab” claims. No disease cure language. No commission rates on public pages. No personal names in the byline.

How to use our guides

  1. Pull your water report (or well test).
  2. Pick a segment via RO vs pitcher or the home hubs.
  3. Open the brand site with Check price to verify live pricing, shipping, and the current performance data sheet.

Start with countertop reverse osmosis (RO) → · About Filter Scout →