Reading the Water Score scale
The Water Score scale runs from 30 to 100, using its original categories and calculation method. Hardness, expressed in French degrees (°f), mainly describes calcium and magnesium content.
The score describes hardness rather than every aspect of water quality. The 12 °f reference point is an internal comfort assumption.
Reference values
The locality pages present reference values recovered on 16 October 2026. That is the recovery date, not a sampling date. Values are updated manually.
Read about the sources, and consult your supplier’s recent reports for information about your supply network and address.
Dated laboratory analyses
Analysis tables are available on 199 locality pages, using AGE, SEBES, AGROLAB and Luxcontrol reports in the project’s collection. Each table separates the supply network, check date and sampling date of each parameter. Sources are identified by laboratory and report reference.
Automated extraction undergoes technical checks for sample identity, units, dates, locality links and consistency. Blocking cases remain under review; conflicting values are not averaged. Technical validation does not establish drinking-water compliance. « < » remains a detection limit.
The Water Score scale and calculator retain their historical hardness reference. The new analyses are not combined into a health score. Data is prepared and included when the website is published, with no real-time measurement or automatic refresh.
Calculator assumptions
The model uses 2 people for “1–2”, 4 for “3–4” and 6 for “5+”. The theoretical annual volume is V = n × 135 × 365 litres, based on 135 litres per person per day.
The annual quantity expressed as calcium carbonate equivalent is TH × V / 100000 kilograms, rounded to the nearest integer, where TH is hardness in °f. This does not measure how much limescale actually deposits inside appliances.
The savings estimates depend on hardness and the number of people. They use internal coefficients, with the factor TH / 25 limited to the range 0.25–1.8. Compare these estimates with your actual expenses; they do not guarantee a particular saving.
Putting the results in context
Your consumption, appliances and maintenance may differ from these assumptions. Find your locality in the municipality and locality directory. The About page explains how to report a correction.