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Bletchley Water Hardness & Quality Report (2026)

Water Hardness

201mg/L
Very Hard

14.1°Clark20.1°fH11.3°dH

Source

mixed

pH Level

7.9

neutral = 7.0

Lead

0.003 mg/L

✓ Below action level

TDS

494.5 mg/L

Est. Daily Cost

£0.46

energy & soap waste

Source: DWI Data Portal · Updated 2026

201mg/L as CaCO₃Very Hard

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 Bletchley, your appliances are currently losing 27% efficiency due to mineral buildup.

ApplianceIn BletchleySoft Water CityEfficiency Loss
Kettle
3 yrs
8.5 yrs-65%
Washing Machine
6.2 yrs
12 yrs-48%
Water Heater
7.6 yrs
15 yrs-49%

Regional Water Comparison

How Bletchley compares to its nearest neighbours

CityHardnessClark°RiskSource
Bletchley, South East201 mg/L14.1°🔴 Very Hardmixed
Milton Keynes, South East199.5 mg/L14°🔴 Very Hardmixed
Newport Pagnell, South East293 mg/L20.6°🔴 Very Hardmixed
Leighton Buzzard, East of England184.5 mg/L12.9°🔴 Very Hardmixed
Aylesbury, South East279 mg/L19.6°🔴 Very Hardmixed

National Benchmark

How Bletchley compares to the United Kingdom average

BenchmarkHardnessAppliance Risk
Bletchley201 mg/L🔴 High
United Kingdom National Avg183 mg/L🔴 High
Livingston Top Rated8.5 mg/L🟢 None

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What Makes Bletchley's Water Unique?

Local geology and source profile

Source: MixedTDS: 494.5 mg/LpH: 7.9

Bletchley, in the Borough of Milton Keynes on the Great Ouse flood plain, is supplied by Affinity Water from the Great Ouse river catchment and the Jurassic Limestone and Chalk Aquifer of the south Bedfordshire and Buckinghamshire country. Affinity Water draws from the Great Ouse at Ely (via the Grafham Water supply scheme) and from licensed boreholes in the Jurassic Great Oolite and Cornbrash Limestone of the Milton Keynes/south Bucks plateau, supplemented by some Cretaceous Chalk groundwater from the Chiltern chalk dip slope. The Ouse catchment carries dissolved calcium from the Jurassic limestone country of south Midlands. The combination of Jurassic limestone groundwater and Ouse-borne calcium produces the moderately hard supply for the Bletchley/Milton Keynes area.

Bletchley's hardness of 201 mg/L (14.1°Clark) reflects the Jurassic Great Oolite Limestone and Great Ouse catchment chemistry. The Jurassic oolitic limestone of the Bucks/Beds plateau contributes moderate dissolved calcium. The Drinking Water Inspectorate (DWI) classifies this supply as hard.

Limescale is a persistent household challenge in Bletchley. At 201 mg/L, limescale forms in kettles within two to three weeks and monthly descaling is advisable. Combi-boiler heat exchangers accumulate deposits steadily — annual boiler servicing and an in-line scale inhibitor are recommended. Showerheads, taps, and shower screens develop regular deposits. Washing-up liquid lathers poorly. Using Calgon monthly in the washing machine and maintaining a regular descaling routine is important limescale management for Bletchley and Milton Keynes households.

Geology & Source: Supplied by Affinity Water from the Great Ouse and Jurassic Limestone catchment — Bletchley's Milton Keynes position on the Great Ouse flood plain draws on Affinity Water's Ouse valley and limestone supply blend from the Jurassic and Chalk country of south Bedfordshire, producing hard water at 201 mg/L (14.1°Clark).

Other South East Water Reports

Frequently Asked Questions

Is Bletchley's water safe to drink?
Yes. Bletchley's water meets all federal safety standards. The hardness is 201 mg/L (Very Hard), which is safe to drink. High hardness affects appliances and taste, but poses no health risk.
Do I need a water softener in Bletchley?
At 201 mg/L (Very Hard), Bletchley's water will cause significant limescale on kettles, washing machines, and water heaters. A water softener or descaler is strongly recommended to extend appliance lifespan and reduce energy bills by up to 27%.
How does Bletchley compare to the United Kingdom average?
The United Kingdom national average is 183 mg/L. Bletchley at 201 mg/L is 18 mg/L above the national average. The softest major city is Livingston at just 8.5 mg/L.