Official Supplier Data: Severn Trent Water • DWI & BS 7593 Standards
Water Hardness in ST21
Official water quality verdict for outcode ST21: classified as Moderately Hard Water (160 PPM), supplied and treated by Severn Trent Water across 1 sectors.
Rating: Moderately Hard Water160 PPM • 11.2° ClarkSupplier: Severn Trent Water-20% below UK average
Outcode Mean Hardness160 PPM11.2° Clark • Moderately Hard Water16.0°fH • 9.0°dH
Outcode ST21 Household Water Quality Verdict & Practical Advice
Domestic tap water in outcode ST21 is officially classified as moderately hard water, averaging 160 PPM (mg/L CaCO₃) or 11.2° Clark, supplied and treated by Severn Trent Water across all 1 postcode sectors (218 postcodes). Readings range from 160 PPM (ST21 6) to 160 PPM (ST21 6) with consistent mineral levels throughout.
☕ Kettle & Tea Quality:
Gradual chalky ring forms in kettles over 2–3 months. Descale quarterly with citric acid crystals to keep heating elements clean.
🚿 Skin & Bathing:
Moderate mineral content is generally gentle on skin, producing normal lather with everyday soaps and shampoos.
🍽️ Appliances & Salt:
Set dishwashers to H02 – H03 to avoid cloudy glassware, and check boiler inhibitor levels at your annual service.
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Protect Your Heating & Appliances in ST21 (160 PPM): Compare Local Specialists
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vs. UK Benchmark-20% Softervs 200 PPM national average
Serving 218 homes and businesses across outcode ST21, mains tap water supplied by Severn Trent Water registers an average mineral density of 160 PPM (16.0°fH / 9.0°dH). Rated as moderately hard water, local water hardness determines how well laundry detergents lather, the rate of scale accumulation in combi boilers, and whether sensitive skin or eczema flares up after showers.
Water hardness is remarkably consistent across all 1 sectors of ST21, with readings holding steady at 160 PPM from ST21 6 through to ST21 6. This uniform profile means every household on the Severn Trent Water network in this zone shares the same appliance settings and kettle descaling routine.
Supplies across ST21 are managed by Severn Trent Water through a balanced mix of lowland river abstraction and regional storage reservoirs. Water hardness fluctuates moderately between wet winter periods and dry summer months, averaging 160 PPM across all 218 local postcodes under strict Drinking Water Inspectorate (DWI) compliance.
Households across ST21's 218 postcodes experience manageable mineral levels. While heating efficiency losses remain mild (4% – 7%), routine descaling of steam irons and thermostatic shower cartridges prevents gradual mineral clogging.
Estimated Annual Household Financial Impact
Limescale & Appliance Operating Costs in Outcode ST21
Based on 160 PPM mineral saturation (Moderately Hard Water), operating heating appliances across ST21's 218 households carries distinct annual economic consequences:
Tap water throughout outcode ST21 is supplied from a unified distribution network managed by Severn Trent Water. With sector ST21 6 presenting an identical mineral concentration of 160 PPM, households across all 218 postcodes share uniform limescale risk profiles and identical appliance salt calibrations (H02 – H03).
Frequently Asked Questions: Water in Outcode ST21
Q: What is the average water hardness in outcode ST21?
Tap water across outcode ST21 averages 160 PPM (mg/L), which equals 11.2° Clark, 16.0°fH, or 9.0°dH. It is officially classified as moderately hard water water supplied by Severn Trent Water.
Q: Is water in ST21 harder than the UK national average?
The UK baseline average is approximately 200 PPM. At 160 PPM, water in outcode ST21 is 20% softer than the national benchmark.
Q: What dishwasher salt setting is recommended for ST21?
For Bosch, Siemens, and Neff dishwashers in outcode ST21 (160 PPM), the recommended softener setting is H02 – H03.
Q: Who manages the municipal water supply in outcode ST21?
Public tap water infrastructure across all 1 sectors in outcode ST21 is distributed and monitored by Severn Trent Water.
All Postcode Sectors in ST21
Select a postcode sector below to view exact water softener salt settings, limescale protection guides, and appliance recommendations.