Water hardness in Lisburn
160 mg/L hard
Tap water in Lisburn is hard: 160 mg/L (9.3 gpg · 9 °dH · 16 °fH).
Source: NI Water, customer tap results 2024,2025 (OpenDataNI, OGL v3.0) (2025-12) · data checked 2026-10-19
Range across supply zones: 26–164 mg/L.
The tap water in Lisburn is provided by NI Water from one of its 24 treatment works, treating lough, river or reservoir water rather than groundwater. Reported hardness is 159.8 mg/L CaCO₃, ranging from 25.7 to 163.6 mg/L between supply zones. Water from sources in the harder parts of the province carries more dissolved calcium and magnesium; expect visible limescale on taps, kettles and in boilers; a softener or scale inhibitor is worth considering, especially for hot-water systems.
UK suppliers report mg/L CaCO₃ and often Clark degrees (1 °Clark = 14.25 mg/L).
Water data
| Total hardness | 160 mg/L |
|---|---|
| Utility | Northern Ireland Water |
How Lisburn compares
- Tap water in Lisburn is 13 % softer than the median of the 471 cities we track in the United Kingdom (185 mg/L).
- By hardness it ranks 259 of 471 in the United Kingdom (1 = hardest); 43 % of these cities have softer water.
- In Northern Ireland it is number 9 of 110 cities; the regional median is 100 mg/L.
- Nearest city with clearly softer water: Hillsborough, 7 km away (23 mg/L).
Ranking of the hardest and softest water in the United Kingdom →
What it means at home
- Fast scale on taps, shower screens and kettle; white spots on glassware.
- Water heater: efficiency loss and element failures within years if unprotected.
- Dry skin and dull hair after showering are common.
- Softener recommended; jug or reverse osmosis for drinking.
How much salt will you use for softening?
Recommended, especially with a heater or boiler: scale cuts efficiency and shortens its life.
Descale a coffee machine or kettle about every 2 months (typical manufacturer guidance for this hardness).
Estimates for planning, not a quote. Check your appliance manual for exact settings.
Dishwasher setting in Lisburn
| Brand | Setting for this water |
|---|---|
| Bosch | H02 |
| Miele | 9 °dH |
| AEG / Electrolux | 2 |
| Beko | 3rd |
| Hoover | S1 |
| 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 Lisburn water hard or soft?
It is hard: 160 mg/L as CaCO₃ (9.3 gpg, 9 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Lisburn 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 Lisburn water?
9.3 gpg, equal to 9 °dH, 16 °fH or 160 mg/L calcium carbonate.
What dishwasher salt setting should I use in Lisburn?
For 160 mg/L (9 °dH) check your manufacturer's table: level 4–5.
Do I need a water softener in Lisburn?
Recommended if you have a water heater, boiler or tankless unit: it saves repairs and detergent.
Source
Source: NI Water, customer tap results 2024,2025 (OpenDataNI, OGL v3.0) (2025-12). Method: own measurement. NI Water, customer tap results 2024,2025 (OpenDataNI, OGL v3.0) · Outdated figure? Tell us