Northampton Water Hardness & Quality Report (2026)
Water Hardness
19.3°Clark27.5°fH15.4°dH
Source
mixed
pH Level
8.4
neutral = 7.0
Lead
0.007 mg/L
✓ Below action level
TDS
808.2 mg/L
Est. Daily Cost
£0.62
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 Northampton, your appliances are currently losing 37% efficiency due to mineral buildup.
| Appliance | In Northampton | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 1.5 yrs | 8.5 yrs | -82% |
| Washing Machine | 3.4 yrs | 12 yrs | -72% |
| Water Heater | 5 yrs | 15 yrs | -67% |
Regional Water Comparison
How Northampton compares to its nearest neighbours
| City | Hardness | Clark° | Risk | Source |
|---|---|---|---|---|
| ▶ Northampton, East Midlands | 274.5 mg/L | 19.3° | 🔴 Very Hard | mixed |
| Milton Keynes, South East | 199.5 mg/L | 14° | 🔴 Very Hard | mixed |
| Leicester, East Midlands | 170 mg/L | 11.9° | 🟠 Hard | mixed |
| Luton, East of England | 275 mg/L | 19.3° | 🔴 Very Hard | groundwater |
| Coventry, West Midlands | 55 mg/L | 3.9° | 🟢 Soft | reservoir |
National Benchmark
How Northampton compares to the United Kingdom average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Northampton | 274.5 mg/L | 🔴 High |
| United Kingdom National Avg | 164 mg/L | 🟠 Moderate |
| Glasgow Top Rated | 15 mg/L | 🟢 None |
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What Makes Northampton's Water Unique?
Local geology and source profile
Northampton's water supply is managed by Anglian Water, drawing from the River Nene catchment in Northamptonshire and the associated Pitsford Reservoir — a large storage reservoir near Brixworth completed in 1956, with a capacity of approximately 4 billion litres. The Nene rises in upland Northamptonshire and flows eastward across the county's ironstone and limestone terrain. Abstracted water is treated at Anglian Water's facilities in the county before distribution to Northampton. A portion of supply is also drawn from the River Great Ouse system via Grafham Water transfers during periods of high demand. Northampton's supply catchment is entirely within the East Midlands agricultural and limestone belt.
Northampton's hardness of 274.5 mg/L (19.3°Clark) results from the Jurassic limestone and ironstone geology of the Nene catchment. Northamptonshire is underlain by Jurassic oolitic limestone and ironstone strata — the same geological band that extends from the Cotswolds through the East Midlands to Lincolnshire — through which the River Nene drains from headwaters to abstraction point. These limestone formations are moderately soluble, and river water in contact with them over its course acquires substantial calcium carbonate concentrations. The result is water classified as hard by the Drinking Water Inspectorate (DWI).
Limescale is a regular and significant household challenge in Northampton. At 274.5 mg/L, limescale deposits form quickly — a visible crust appears in kettles within two to three weeks, and fortnightly descaling with a proprietary descaler is advisable. Combi-boilers face meaningful limescale accumulation in the heat exchanger, and annual servicing with limescale inspection is strongly recommended, along with fitting a scale inhibitor to the boiler cold feed. Washing-up liquid lathers poorly at this hardness. Showerheads, taps, and bathroom tiles require regular descaling attention. Northampton homeowners should consider a magnetic water conditioner or a full water softener for effective long-term limescale management.
Geology & Source: Supplied by Anglian Water from the River Nene and Pitsford Reservoir — water from the Northamptonshire Jurassic limestone and ironstone belt produces hard water at 274.5 mg/L (19.3°Clark), the result of prolonged contact with soluble limestone geology.