Affiliate Disclosure

How WaterByTheBook makes money, stated plainly. Last updated 28 July 2026.

Some outbound links on this site are affiliate links. As an Amazon Associate we earn from qualifying purchases. If you buy something after following one, we may receive a small commission. It costs you nothing extra — the price you pay is the same either way.

Affiliate links are marked sponsored and nofollow in the page’s HTML, which is the machine-readable disclosure search engines expect. In plain terms: anything that sends you to a retailer to buy a filter should be assumed to be an affiliate link. Links to manufacturers’ spec sheets, certification databases and government data are not.

Why this does not bend the advice

The obvious worry with affiliate income is that it quietly decides what gets recommended. Here is the structural answer, not just a promise:

  • Recommendations are driven by certification, not commission. Which filter fits is determined by the manufacturer’s own fitment data, and what it removes is determined by the NSF, IAPMO and WQA certification listings — we distinguish NSF-LISTED from manufacturer-claimed every time. None of those sources knows or cares whether we earn a commission.
  • We say when the cheaper thing is the right thing. Aftermarket cartridges are often the correct answer over the brand-name one, a pitcher is sometimes enough, and plenty of water problems need no purchase at all. Those answers pay us less, and we publish them anyway.
  • We name the downsides. Reverse osmosis wastes water to drain. A softener will not fix heavy iron on its own. If a product has a real drawback, it goes in the guide.
  • We do not accept payment in exchange for a recommendation, a ranking or a review. No sponsored posts, no paid placement, no “send us a unit and we will write about it” arrangements.

If you ever find a recommendation on this site that only makes sense as a way to earn a commission, that is a bug and we want to hear about it: waterbythebook@gmail.com.

What happens after you click

Once you follow an affiliate link you are on the retailer’s site, under their privacy policy and their tracking, and they may set cookies we neither control nor see. The purchase itself is between you and them: they take the payment, ship the item, honour the warranty and handle returns. We are not a party to it. See our privacy policy for what happens on this side of the link, and our terms of use.

Because the alternative is worse. The usual ways to fund a site like this — display advertising, sponsored reviews, selling reader data — all pull harder against the reader than a commission does. Affiliate income means the site is free, carries no ads, sets no cookies and sells nothing about you. If you would rather not contribute, use the guides and buy wherever you like; the research is free either way.