About

The Water Dictionary is an independent reference for water mineral composition. It covers bottled water, tap water, and famous water profiles used in brewing, coffee, baking, and aquariums.

The site provides mixing recipes that recreate well-known water profiles using bottled waters available at your local supermarket. Enter a UK postcode to see what's in your tap water. Browse over 130 bottled waters with full mineral breakdowns.

What we cover

• 135 bottled waters across 16 markets, 108 with complete 6-ion profiles
• 24 target water profiles for brewing, coffee, baking, and aquariums
• 1,300+ UK tap water zones across 19 water companies
• 1,500+ outcode pages with mineral data, hardness classification, and practical guidance

How recipes work

Recipes are generated by a solver that tests combinations of bottled waters at varying ratios and optimises for the closest match to each target profile. Each ion (calcium, magnesium, sodium, sulfate, chloride, bicarbonate) is scored with a tolerance band — small deviations are treated as negligible, larger deviations are weighted by how much they matter for the use case.

Where the target profile can't be reached with bottled water alone, we say so. The match quality label and deviation bars on each recipe show exactly where the blend falls short and whether salt additions would help.

Data sources

Bottled water mineral data comes from manufacturer labels, official analysis reports, regulatory filings (Defra natural mineral water register, FDA water quality reports), and reference databases including finewaters.com, mineralwaterfit.com, and Open Food Facts. Each profile records its canonical source and date.

Tap water data comes from annual water quality reports published by each UK water company, supplemented by zone-level PDF reports and LSOA-level regulatory data. Estimated values (derived from hardness or ion balance rather than directly measured) are marked with a ~ prefix.

Target profiles come from published water analyses, brewing literature (Palmer & Kaminski), SCA water quality standards, aquarium care guides, and regional baking research.

Limitations

Water composition is a point-in-time measurement. Bottled water profiles can shift between bottling runs. Tap water varies seasonally. We record when each value was last verified, but the numbers on this site are reference values, not guarantees.

This site is a recipe and reference tool. It is not a source of health advice. If you have concerns about your water quality, contact your water company or a qualified professional.

Licensing

All water profile data is available under the Creative Commons BY 4.0 license. You are free to use, share, and adapt the data with attribution.