Water Hardness in London
London has hard water at 260 mg/l CaCO₃. This is above the UK national average of 197.72 mg/l. You may notice limescale buildup on taps, in kettles, and around showerheads.
260
mg/l CaCO₃
HardUK average: 197.72 mg/l
260
0 (Soft)200 (Hard)400+ (Very Hard)
What Does Hard Water Mean?
With a hardness of 260 mg/l, London has hard water. This level of hardness is common in areas supplied from chalk and limestone aquifers in the South East of England.
You will likely notice white limescale deposits on taps, showerheads, and inside your kettle. Over time, limescale can reduce the efficiency of boilers and heating systems, increasing energy costs. A water softener can help prevent these issues.
Water Supplier
- Water Company
- Thames Water
- Supply Zone
- City (NLE7)
- Source Type
- River
- Treatment Works
- City Treatment Works
Full Water Quality Report for London
See all 8 water quality parameters including pH, chlorine, lead, nitrate, fluoride and more.
Frequently Asked Questions
Is water hard in London?▾
Yes, London has hard water at 260 mg/l CaCO₃, classified as "Hard". You will likely notice limescale buildup on taps, in kettles, and around showerheads. A water softener or regular descaling can help manage this.
What is the hardness of water in London?▾
The water hardness in London is 260 mg/l CaCO₃ (milligrams per litre of calcium carbonate). This is classified as "Hard" on the standard UK scale and is above the national average of 197.72 mg/l. Water is supplied by Thames Water from river sources.
Who supplies water to London?▾
Water in London is supplied by Thames Water, which covers the London and Thames Valley region. The water is sourced from river abstraction and treated at City Treatment Works before distribution.