We define the treatment job first
Before product discovery, we define the water source, installation point, treatment goal, known contaminant or aesthetic problem, household demand, pressure and flow constraints, space, maintenance tolerance, and budget. A shower filter, pitcher, refrigerator cartridge, under-sink unit, whole-house system, softener, UV reactor, and reverse-osmosis system are not substitutes for one another.
Candidate discovery and identity
We search the exact product class and buyer job. Exact reviews are locked to the imported model. A-vs-B comparisons require independent evidence for both named sides. Unrelated products from the same brand and mismatched replacement cartridges are rejected.
Evidence checks
Where available, we record filtration technology, exact certification wording and standard numbers, model-specific reduction claims, capacity, lifespan, flow, dimensions, compatibility, pressure requirements, installation, replacement cost and availability, reverse-osmosis wastewater ratio, warranty, price, availability, ratings, and recurring buyer-feedback patterns.
Ownership cost and awards
Purchase price is only one part of value. We consider replacement frequency, cartridge price and access, water or salt use, electricity where relevant, maintenance, installation, and expected service life. Awards describe a specific buyer fit. The Best Overall winner remains consistent across the research plan, table, article, metadata, and verdict.
What we refuse to infer
We do not convert tested into certified, component certification into system certification, or one contaminant claim into a broader promise. We do not claim a product makes any water safe, removes all contaminants, prevents disease, or guarantees safe drinking water.