How we research, fact-check and review

Sources we accept

• Manufacturer manuals, service handbooks and support articles.
• Government agencies, such as the EPA, CDC and the Department of Energy.
• Code bodies and the standards they publish.
• University extension programs.
• Named cost publishers, for prices and labor ranges.

We don't cite forums, anonymous blogs or AI answers. Each page lists its sources at the bottom with the date we last checked them.

Every number has a source

Every number on a page, from a pressure setting to a price range, is tied to one of the sources listed on that page. If we can't find a source for a number, the number doesn't go on the page.

A separate fact-check before publishing

Before a page goes live, a check run separately from the writing compares each claim with the source it cites. For our first 200 pages that meant 2,002 claims checked against their sources. Most problems found were wording that went further than the source did, and those sentences were rewritten to say only what the source says.

Trade review

Pages on plumbing and heating topics (water heaters, wells and pumps, water softeners and treatment, water quality) are reviewed by Eric Jackov, a plumbing and heating professional.

His review does not cover electrical work. Generator, interlock, transfer switch and battery pages are labeled as awaiting an electrician's review until one has checked them.

What the labels mean

• Reviewed: the reviewer named on the page checked this exact text on the date shown.
• Updated since review, re-review pending: the page changed after the review. The new text has not been checked by the reviewer yet. We track this with a fingerprint of the reviewed text, so the label changes as soon as an edited page is published.
• Awaiting trade review: the page is sourced and fact-checked, but no trade professional has checked it yet.

How often we re-check costs

We re-check every price and labor range at least once a year, and sooner when a source publishes new figures. The date at the top of each page shows when it was last updated.

See something wrong? The corrections page explains how to tell us.