Water hardness in Rotherham
210 mg/L very hard
Tap water in Rotherham is very hard: 210 mg/L (12.3 gpg · 11.8 °dH · 21 °fH).
Source: Yorkshire Water — domestic drinking water quality (Stream open data, CC BY) (2026-10) · data checked 2026-10-19
Range across supply zones: 61–307 mg/L.
Rotherham is supplied by Yorkshire Water, whose supply comes from a mix of upland reservoirs, rivers and boreholes; the company says water in the west comes off the moors while the east relies mostly on boreholes and groundwater. Reported hardness is 210.3 mg/L CaCO₃, ranging from 61.2 to 307.2 mg/L between supply zones. The harder supply reflects borehole and groundwater sources, which pick up calcium and magnesium from the rock; it is hard to very hard water, so scale builds quickly on kettles, showers and heating elements and shortens appliance life unless treated.
UK suppliers report mg/L CaCO₃ and often Clark degrees (1 °Clark = 14.25 mg/L).
Water data
| Total hardness | 210 mg/L |
|---|---|
| Utility | Yorkshire Water |
How Rotherham compares
- Tap water in Rotherham is 14 % harder than the median of the 471 cities we track in the United Kingdom (185 mg/L).
- By hardness it ranks 222 of 471 in the United Kingdom (1 = hardest); 53 % of these cities have softer water.
- In Rotherham it is number 6 of 9 cities; the regional median is 242 mg/L.
- Nearest city with clearly softer water: Treeton, 5 km away (116 mg/L).
- Nearest city with clearly harder water: Mexborough, 8 km away (286 mg/L).
Ranking of the hardest and softest water in the United Kingdom →
What it means at home
- Severe scale: heater elements and washing-machine heaters fail early.
- Detergent use is very high; taps and screens coat within days.
- Dishwasher at maximum salt setting.
- An ion-exchange softener is practically essential; RO for drinking water.
How much salt will you use for softening?
Yes. At this hardness a softener pays for itself through appliance life and detergent.
Descale a coffee machine or kettle about every 1 months (typical manufacturer guidance for this hardness).
Estimates for planning, not a quote. Check your appliance manual for exact settings.
Dishwasher setting in Rotherham
| Brand | Setting for this water |
|---|---|
| Bosch | H03 |
| Miele | 12 °dH |
| AEG / Electrolux | 3 |
| Beko | 3rd |
| Hoover | S2 |
| LG | H2 |
From each brand's manual for the model family named in the source; your model may differ, so check its manual. All brands and how to change the setting →
FAQ
Is Rotherham water hard or soft?
It is very hard: 210 mg/L as CaCO₃ (12.3 gpg, 11.8 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Rotherham safe to drink?
Hardness is not a health issue; it is about limescale, taste and appliances. Mains water must meet national drinking-water standards. UK suppliers report mg/L CaCO₃ and often Clark degrees (1 °Clark = 14.25 mg/L).
How many grains per gallon is Rotherham water?
12.3 gpg, equal to 11.8 °dH, 21 °fH or 210 mg/L calcium carbonate.
What dishwasher salt setting should I use in Rotherham?
For 210 mg/L (11.8 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Rotherham?
Yes, unless you are only passing through: scale damages appliances within a few years.
Source
Source: Yorkshire Water — domestic drinking water quality (Stream open data, CC BY) (2026-10). Method: own measurement. Yorkshire Water — domestic drinking water quality (Stream open data, CC BY) · Outdated figure? Tell us