About Water Quality Rank

Water Quality Rank answers one question: which water is actually clean? We rank 2,735 bottled waters, 463 water filters and 18,718 US tap water locations on a 0–100 purity score.

Where the data comes from

Product data, lab reports and contaminant measurements come from Oasis, which collects third-party lab reports from brands and independent testing. 310 of the waters we rank have a lab report on file. Tap water data comes from utility testing reports. Contaminant limits come from the EPA and health guidelines from public health agencies.

How scores work

Waters are scored on seven factors: a lab report being on file, contaminants versus legal limits and health guidelines, water source, mineral preservation, packaging material, cap material and PFAS testing. Filters are scored on verified contaminant removal, certifications and lab evidence. The full breakdown is on how water scores work and how filter scores work.

Independence

Brands cannot pay to change their score or their position. Rankings are generated from the data, so every list on the site updates when new lab reports arrive.

Not medical advice

Scores compare products against each other and against health guidelines. They are not a safety certification. If you have a medical condition, talk to your doctor about your water.