Editorial Policy

Where our facts come from

Every factual claim on a page we publish comes from a primary source: a federal agency such as EPA, CDC or USGS, a state agency, the text of a regulation, or a standards body. We don't build pages on other websites' summaries, competitor guides or forum posts.

Each source is listed at the end of the page with its publisher and the date we retrieved it. That date matters because agency pages change. If a source has moved or no longer says what we cited it for, the claim comes off the page until we can source it again.

Numbers come from data, not from memory

Regulatory values, such as a maximum contaminant level or an action level, are never typed into a page by hand. They live in one versioned data set, and each page reads them from there. Each value in that data set records its source, its status (in force, proposed, future or challenged) and the date we last checked that status.

For example, EPA's National Primary Drinking Water Regulations are legally enforceable standards and treatment techniques that apply to public water systems. When a page shows one of those limits, it shows the value our data holds for it, with its status. If the data changes, every page that shows the value changes with it, so two pages can't disagree about the same limit.

The same applies to prices and lab details. They come from our lab data, each with its own source and check date, and a fact without a source is not shown.

The review gate

No page is meant to rank in search results until a named reviewer has approved it. Until then, the page tells search engines not to index it.

A reviewer approves one exact version of a page. If anything in the page changes afterward, even a single word or source, that approval no longer covers it, and the page goes back out of search until a reviewer approves the new version. If reviewers record different decisions over time, the latest decision is the one that counts.

The same gate covers the plain-language explanations we show next to your results, so a change to an explanation also needs a new approval.

How we use AI in drafts

Drafts are AI-assisted from cited primary sources, then fact-checked and approved by the named reviewer.

In practice, the sources are gathered first. A draft is written only from what those sources say, and every number is either read from our data or tied to a listed source. The reviewer then checks the draft against the sources and the data before approving it.

Once a reviewer approves a page, its byline reads "Reviewed by", then the reviewer's name and credentials, then "Updated" with the date the page last changed. The byline names the person who approved the page. We don't add a separate author line, and no page claims expert review before a reviewer has approved it.

Plain language and its limits

We write for the person holding the sample bottle: short sentences, everyday words, and the answer first. Technical terms are explained the first time they appear.

We don't give medical advice. Our pages can tell you how a result compares with a benchmark and what people usually do next, such as retesting or contacting a certified lab, but questions about your health belong with a health professional.

We don't call water "safe" or "unsafe" on its own. A result is described against a named benchmark, such as being below EPA's legal limit or above a health guideline, because "safe" means little without saying safe by which measure.

We never recommend treatment without a certified-lab result, and when results come back below every benchmark, "no treatment needed" is a valid answer.

How we keep pages current

Some rules change faster than others. We check the status of the lead and PFAS rules every month, including EPA's Lead and Copper Rule Improvements page, and lead and PFAS pages show a box with each benchmark's status as of the date we last checked it.

Every lab price carries a check-by date, set when we verify it. A price that is not confirmed again by that date is hidden rather than shown out of date.

When a benchmark value, its status or one of our result explanations changes, the change is written to our corrections record, and every approved page or explanation that relies on that contaminant goes into a queue for a reviewer to look at again.

Corrections

If we get something wrong, we fix it and say so. The corrections and updates log lists each correction and regulatory update with its date. To report a possible error, contact us through our contact page with the page and, if you can, the source that shows the correct information.

Independence

What we earn never shapes what we write. Health guidance comes from published benchmarks and our versioned data, and no lab, manufacturer or partner can pay to change a page, a test plan or the meaning of a result. Lab rankings never use what we earn or whether a lab is a partner. How we make money explains where our revenue comes from, and our methodology explains how labs are verified and ranked.