Review Methodology · 2026 edition
Every ranking on Clean Living Lab follows the same process. No one-time reviews, no "top 10" lists assembled from product pages, no affiliate dashboard dictating the order. Here's the work behind it.
We pick a product category (e.g. under-sink PFAS filters). We source units ourselves — bought retail, borrowed, or requested for testing. We run them against independently verifiable lab data (NSF, WQA, third-party PFAS assays, CARB certification, EPA allowable limits). We live with them for at least 30 days in real homes. Then we rank what's left.
Rankings start from a reader question ("what's the best filter for a rental?") — not from a brand pitch. We define the category, the realistic price ceiling, and the contaminants or outcomes that matter for that use case before we look at any specific product.
Candidates come from three places: NSF/WQA certification databases, reader nominations, and our own market scan. Brands cannot buy their way onto the test list. We intentionally include at least one budget option and one "over-engineered" option in every roundup, because the floor and ceiling tell you something about the middle.
Every claim a product makes — "removes PFAS," "NSF 53 certified," "99.9% chlorine reduction" — gets checked against the certifying body's public database. Claims that can't be verified are either dropped or flagged in the review. We link to the certification PDF when one is available.
Default is: we buy the product. When a brand sends a test unit, we disclose it on the review page and compare the unit's performance against the same model purchased at retail (when possible) to rule out "cherry-picked hardware." Samples do not guarantee a recommendation.
Products are installed in real homes (ours, contributors', reader volunteers') and used daily for at least 30 days. For filters, that means tracking flow rate, taste, install difficulty, leak incidents, and any support-ticket experience. For appliances, it means watching noise, maintenance cadence, and real-world energy use.
Each category has a published rubric — e.g. for water filters: contaminant removal (40%), value per gallon (20%), installation friction (15%), maintenance cost (15%), manufacturer support (10%). Scoring is the same whether we're affiliated with the brand or not.
Rankings get a full re-test at least once a year, and we update earlier if a product changes hardware, gets recalled, loses certification, or develops a support issue at scale. You'll always see an "Updated" date at the top of every ranking page.
Water filters. We require NSF 42 (aesthetic), NSF 53 (health), and — for anything marketed as PFAS-reducing — independent lab data showing sub-EPA-limit output. Point-of-use RO systems must publish recovery ratio; we penalize anything under 1:3.
Air purifiers. We require CADR figures for smoke, dust, and pollen; AHAM verification; and CARB certification for units sold in California. "Ionizer" and "plasma" units are excluded unless CARB-listed as not producing ozone above 0.050 ppm.
Clean-home products. EWG, MADE SAFE, or equivalent third-party ingredient verification. We don't accept "non-toxic" as a self-declared claim.
Supplements. NSF Certified for Sport, USP Verified, or equivalent batch-level third-party testing. No proprietary blends. No structure/function claims we can't substantiate.
Reviews are written by named editors with relevant backgrounds (water, air, household chemistry, nutrition). Product testing is done in-house; lab analysis, where applicable, is outsourced to accredited labs. See About for team bios.
We've made them. When we get something wrong — a product that seemed great in testing but failed in readers' homes; a certification we misread; a recall we missed — we correct the page, note the date of the correction at the bottom, and email readers who subscribed to that category's alerts.