High Wycombe Water Hardness & Quality Report (2026)
Water Hardness
12.1°Clark17.3°fH9.7°dH
Source
mixed
pH Level
7.7
neutral = 7.0
Lead
0.002 mg/L
✓ Below action level
TDS
388.3 mg/L
Est. Daily Cost
£0.39
energy & soap waste
Source: DWI Data Portal · Updated 2026
0–60
mg/L
Soft
61–120
mg/L
Moderately Hard
121–180
mg/L
Hard
180+
mg/L
Very Hard
Appliance Damage Report
In High Wycombe, your appliances are currently losing 23% efficiency due to mineral buildup.
| Appliance | In High Wycombe | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 3.9 yrs | 8.5 yrs | -54% |
| Washing Machine | 7.2 yrs | 12 yrs | -40% |
| Water Heater | 8.7 yrs | 15 yrs | -42% |
Regional Water Comparison
How High Wycombe compares to its nearest neighbours
| City | Hardness | Clark° | Risk | Source |
|---|---|---|---|---|
| ▶ High Wycombe, South East | 173 mg/L | 12.1° | 🟠 Hard | mixed |
| Marlow, South East | 242.5 mg/L | 17° | 🔴 Very Hard | mixed |
| Beaconsfield, South East | 257 mg/L | 18° | 🔴 Very Hard | mixed |
| Maidenhead, South East | 255.5 mg/L | 17.9° | 🔴 Very Hard | mixed |
| Burnham, South East | 299 mg/L | 21° | 🔴 Very Hard | mixed |
National Benchmark
How High Wycombe compares to the United Kingdom average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ High Wycombe | 173 mg/L | 🟠 Moderate |
| United Kingdom National Avg | 183 mg/L | 🔴 High |
| Livingston Top Rated | 8.5 mg/L | 🟢 None |
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What Makes High Wycombe's Water Unique?
Local geology and source profile
High Wycombe, in Buckinghamshire in the Wye Valley of the Chiltern Hills, is supplied by Affinity Water, the water-only company serving the Chilterns, Thames Valley, and Hertfordshire. Supply is drawn from licensed boreholes sinking into the Chiltern Hills Chalk Aquifer — the Cretaceous Upper Chalk that forms the principal geology of the Chiltern Hills and their dip slope toward the Thames. Key abstraction sites in the Wye valley and the surrounding chalk country access groundwater that has percolated through the chalk hillsides above High Wycombe. This chalk groundwater is blended with Thames-derived surface water from Affinity Water's broader network. Water is treated at local facilities before distribution to High Wycombe and the Wye valley communities — a town historically noted for its furniture-making industry, which used the soft waters of the Chiltern valleys.
High Wycombe's hardness of 173 mg/L (12.1°Clark) reflects the Chiltern Chalk contribution to its supply. The Chilterns are formed from Cretaceous Upper Chalk — a highly porous, calcium-rich limestone that is the primary aquifer source for much of the Chilterns and the Thames Valley to its south. Groundwater in the chalk carries dissolved calcium carbonate from many years of percolation, though High Wycombe's hardness at 173 mg/L is notably lower than the extremely hard chalk supplies of the deeper aquifer cities (Cambridge, Ipswich), reflecting the local Chiltern chalk depth and aquifer residence time. The supply is classified as moderately hard by the Drinking Water Inspectorate (DWI).
Limescale requires regular attention in High Wycombe homes. At 173 mg/L, limescale forms in kettles within three to four weeks and monthly descaling is advisable. Combi-boiler efficiency is meaningfully affected by limescale accumulation in the heat exchanger — annual servicing with a limescale inspection and an in-line scale inhibitor are recommended. Showerheads, taps, and bathroom surfaces develop steady limescale deposits. Washing-up liquid lathers moderately. Using Calgon monthly in the washing machine and keeping descaling products to hand is standard practice for High Wycombe households.
Geology & Source: Supplied by Affinity Water from the Chiltern Hills Chalk Aquifer — High Wycombe sits in the heart of the Chiltern chalk escarpment, where deep boreholes access groundwater percolated through ancient Cretaceous chalk, producing moderately hard water at 173 mg/L (12.1°Clark).