Water hardness in York
For York, Yorkshire Water publishes 98.8 mg/L calcium rather than a comparable total-hardness figure.
The utility itself classes the water as hard.
How hardness is classified
There is no European classification; each country sets its own bands. Here is how the country itself classifies it, and how the international scale compares:
How United Kingdom classifies it
Internationally, from the WHO and the US Geological Survey
Does the figure apply at your address?
Probably, but not certainly. A utility publishes one figure for a supply zone, and a large city is rarely one zone. Buildings with their own softening plant differ again.
Yorkshire Water publishes calcium, not CaCO3; their own classification is 'hard'
The figure for your address or postcode is available directly from Yorkshire Water — and it is often printed on the water bill too.
A hardness test strip from a chemist or hardware shop costs a few euros and settles it in a minute. That is also the only way to know what comes out of your own tap rather than what leaves the waterworks.
What it means day to day
How much limescale you get depends on which waterworks supplies your street.
Hard water is not a fault
Hardness is not a safety question. Hard water is fine to drink; it just leaves more limescale.
The calcium and magnesium that make water hard are the same minerals a diet needs, and drinking water counts towards the daily intake of both. The WHO reviewed how much in Calcium and magnesium in drinking-water.
A thin carbonate layer on the inside of a pipe also protects the metal underneath from corroding. Water softened to nothing is harder on plumbing, not easier.
The water is fine to drink either way: Is the tap water in York safe to drink?
Where the figure comes from
Published by Yorkshire Water, as of 2024.
The figure is total hardness, which counts every calcium and magnesium compound in the water. Some utilities also publish carbonate hardness, the part bound to carbonic acid, which is the share that forms limescale when the water is heated.