Clean Water Guide Clear advice. Cleaner water.

How we research

Clean Water Guide is an independent, UK-focused water filter resource. We exist to answer one question honestly: what should you actually buy?

We want to be upfront about our method, because it's what our credibility rests on. We are a research-and-synthesis site, not a testing lab. We do not install units in our own kitchens or take TDS readings ourselves. Instead, we do the legwork of gathering, verifying and comparing the evidence that already exists — so you don't have to wade through dozens of conflicting, mostly US-based reviews.

Our five-step method

  1. Specs & certifications. We start with manufacturer specifications and, crucially, independent certifications — NSF/ANSI 42, 53, 58 and 372, plus UKCA marking. We cite the standard behind every performance claim rather than repeating "removes 99%."
  2. UK pricing. We record the actual current UK price in £, on a stated date — never a converted-from-dollars guess — and work out the real annual filter cost.
  3. UK context. We assess each product for British realities: water hardness by supply area (using DWI and water-company data), under-sink cabinet fit, power requirements, and UK regulations (DWI, not the US EPA).
  4. Verified owner reviews. We synthesise feedback from Trustpilot, Amazon UK and UK forums — including the negatives, such as customer-service complaints. A balanced picture matters more than a glowing one.
  5. Consistent comparison. Every product is scored against the same criteria, so our rankings are explainable, not arbitrary.

How we make money

Some of our links are affiliate links: if you buy through them, we may earn a commission at no extra cost to you. This never changes which products we recommend or how we rate them — our rankings are decided before any commercial consideration, and we'll happily tell you when the cheaper option is the better buy. You'll see a clear disclosure on every page that contains affiliate links.

Keeping it current

Prices change and new models launch. Every review carries a "Last updated" and "Price checked" date, and we revisit our top recommendations regularly. If you spot something out of date, please tell us at hello@cleanwaterguide.co.uk.