Recommendations should follow the evidence—not the other way around.
The Water Filter Guide helps homeowners evaluate water testing and filtration for municipal supplies and private wells. This page explains how we research claims, assess products, handle affiliate links, and correct mistakes.
Two water sources. Different questions.
For homes served by municipal water, we encourage readers to start with their utility’s Consumer Confidence Report, understand what that report does and does not describe, and consider household plumbing or point-of-use testing when relevant. A report describing the utility’s water does not automatically establish conditions at every individual faucet.
For private wells, we emphasize appropriate testing through qualified laboratories, location-specific risks, and equipment selection based on measured water chemistry. Private wells generally are not regulated under the same federal drinking-water rules that apply to public water systems.
We do not infer that water is safe—or unsafe—solely from its smell, color, taste, or the fact that it comes from a particular source. We distinguish cosmetic and operational concerns from potential health concerns.
What we use to support a claim.
Government guidance
We prioritize relevant information from agencies such as the EPA, CDC, USGS, and state or local health departments for water quality, testing, and health-related questions.
Exact-model documentation
We consult manufacturer manuals, specification sheets, operating requirements, and published maintenance information. A claim about one model does not automatically apply to an entire brand.
Certification scope
Where a certification matters, we aim to verify the specific model and contaminant-reduction claim in the relevant independent certification directory. A standard number alone is not proof of every performance claim.
Suitability conditions
We look for operating limits and relevant variables such as flow, pressure, hardness, pH, iron, sediment, and other feed-water conditions when they affect a system’s suitability.
Ownership, not just price
Comparisons should consider consumables, replacement intervals, servicing, wastewater or backwash where relevant, and installation constraints. Unavailable costs are labeled as unknown.
What we cannot verify
We distinguish independently supported information from manufacturer claims, estimates, and unknowns. We do not manufacture test results, prices, ratings, or firsthand experience.
How water testing informs our guidance.
Not every water problem calls for the same test or treatment. We distinguish quick screening tools from laboratory analysis and do not present inexpensive strips as a substitute for a suitable certified laboratory when health-related contaminants or major treatment decisions are involved.
Sampling instructions can depend on the contaminant and the laboratory. For example, a first-draw lead sample and a bacteriological sample may require different procedures. We encourage readers to follow the laboratory’s instructions rather than a universal one-size-fits-all checklist.
Explore water testing →- City waterStart with the utility’s report; assess whether the household tap or plumbing needs additional investigation.
- Private wellUse appropriate laboratory testing based on baseline recommendations and local risks.
- Specific contaminantConfirm what was actually measured, in which units, and whether the test method suits the decision.
- After treatmentConsider appropriate follow-up testing to verify performance rather than assuming a purchase solved the problem.
How we evaluate filtration products.
When an article compares equipment, the evaluation should be tailored to the task. A drinking-water filter for a single faucet and a whole-house iron-removal system cannot be meaningfully ranked by the same generic checklist.
Our product guides aim to explain who a system may suit, who should avoid it, what conditions matter, and which facts remain unverified. We do not claim to have purchased, installed, or laboratory-tested a product unless a specific page documents that work.
Comparison criteria may include
- Documented contaminant-reduction performance and certification scope
- Water-source and feed-water compatibility
- Rated flow, capacity, pressure, and installation needs
- Replacement media, maintenance, and recurring costs
- Availability of reliable manuals and manufacturer support
- Meaningful alternatives, including no-purchase or professional-testing options
What happens when information changes?
Specifications, product availability, standards, and agency guidance can change. We aim to correct factual errors when identified and revise advice when stronger evidence warrants it. A correction is not the same as changing a visible date without substantive review.
Report an issue →No invented scores, star ratings, laboratory results, credentials, or claims of hands-on experience.
We explain that a filter’s effectiveness depends on the contaminant, operating conditions, installation, and maintenance.
Readers can flag an outdated manual, broken source, incorrect model number, or unclear statement through our contact page.
Federal limits for regulated public-water systems are not automatically legal requirements for private wells; relevant state requirements and health guidance may differ.
Primary resources readers can check.
These organizations provide foundational guidance and directories. Their inclusion does not mean they endorse this website or any product we discuss.
Educational information only. We cannot determine the safety of your water remotely, and our content does not replace appropriate laboratory testing, public-health guidance, or qualified professional assessment.