How We Research

Well water affects your family's health, so we hold our guides to a clear standard. Here is how we put them together.

Sources we use

• Government and public health bodies: the EPA, the CDC and state health departments, for contaminant limits and health guidance.
• University extension services: for practical, region-specific advice on wells, testing and treatment.
• Certification listings: NSF/ANSI and IAPMO listings, to check what a product is actually certified to reduce.
• Manufacturer spec sheets and manuals: for flow rates, capacities, media life and maintenance needs.

What we will and won't claim

We only say we have tested a product when we have. When a comparison is based on specifications, certifications and published data, we say so. We never invent test results, ratings or reviews.

Certification matters more than marketing

"Removes 99% of contaminants" means little on its own. We check which contaminants a system is certified to reduce, to which standard, and at what flow rate, and we point out where marketing claims go further than the certification.

Keeping guides current

Products, prices and guidance change. We review our guides regularly and show the date each one was last updated.

Corrections

If you find an error, please tell us. We fix confirmed mistakes promptly and note significant corrections on the page.

Not a substitute for professional advice

Our guides are general information. If a lab test shows bacteria, nitrates, arsenic or another health risk, follow your state or local health department's advice and consider a certified water treatment professional.