How We Research and Write Our Guides

This page explains how PureFlow Lab researches products and what you can and cannot expect from our guides.

What we do not do

• We do not test products. We have no lab and we do not install systems for review. We do not publish our own TDS readings, flow measurements, or contaminant results.
• We do not accept free products or paid placements.
• We do not give medical advice. If a health concern is behind your water-quality question, talk to your doctor or your local health department, and consider a certified lab water test.

Where our information comes from

• Manufacturer specifications. Capacity (GPD), stages, drain ratio, dimensions, and filter life come from the maker’s own spec sheets or product pages, and we attribute them (“per iSpring”).
• Certifications. NSF/ANSI certification claims are checked against the manufacturer’s certification statement or the certifier’s listing. An RO system can be certified for some contaminants and not others, so we name the standard (for example NSF/ANSI 58) rather than saying “NSF certified” in general.
• Retail listings. Where a detail only appears on the product listing, we say it comes from the listing.
• Public health sources. Background on contaminants and water safety comes from the EPA, CDC, and NSF.

Prices

We do not print prices in our guides because they change daily. Use the “Check price” buttons for the current price.

How recommendations are made

Picks are organized by situation (tankless vs. tank, countertop vs. under-sink, alkaline remineralization, well water) rather than a single ranking. Each pick states the documented specs that support it and the trade-offs you should know about.

Corrections

Products get discontinued and specs change. If you find something wrong, tell us and we will verify it against the source and update the page.