Water hardness in Blackburn (North West England): 4.59°fH, quality index 10/10. Official UK data.
✓ Compliant with DWI standardsBlackburn has very soft water (4.59°fH). No limescale issues at all: your appliances will last longer without special care.
UK tap water is subject to the Water Supply (Water Quality) Regulations 2018, overseen by the Drinking Water Inspectorate (DWI). The sanitary compliance indicator shows whether the latest official analyses found any non-conformities on parameters such as bacteriology, nitrates, pesticides or heavy metals.
The TH (Total Hardness) measures calcium and magnesium content. Below 10°fH: soft. From 10 to 20: moderately soft. From 20 to 27: slightly hard. From 27 to 35: hard. Above 35: very hard. Blackburn's water is soft at 4.59°fH.
Maintenance budget: ~£13/year
For 2 persons, water at 4.59°f deposits around 0.2 kg of limescale per year in your appliances. Estimated cost in descalers, salt and filters.
Calcium: ~7 mg per litre
Your water provides 7 mg of calcium/L, which is 1% of the recommended daily intake.
Filtration not required
Your soft water does not require filtration. A jug filter remains useful for taste.
The tap water hardness in Blackburn is 4.59°fH, corresponding to soft water. In comparison, the England average in our dataset is 18.1°fH and the North West England region average is 5.91°fH.
Yes. The water in Blackburn meets DWI sanitary standards (Water Supply (Water Quality) Regulations 2018). The hardness of 4.59°fH affects taste and appliance maintenance, not safety. Water in Blackburn is supplied and monitored by United Utilities.
At 4.59°fH, a water softener is optional in Blackburn. Regular descaling (every 1 to 3 months depending on appliance) and a pitcher filter are sufficient to limit limescale buildup.
A hardness of 4.59°fH corresponds to approximately 7 mg of calcium per litre, or 1% of the recommended daily intake. This calcium is not dangerous; hard water can even contribute to your daily calcium intake.
Water in Blackburn is supplied by United Utilities. Data source: United Utilities 2025.
Data: United Utilities official zone-level hardness reports (2025). Values verified via DWI drinking water quality database.