Soft WaterSouth West WaterSouth West

Exeter Water Hardness Report

Official mineral water quality analysis, local catchment breakdown, appliance salt calibration, and postcode outcode directory for Exeter.

Average City Tap Water RatingUpdated 24 June 2025
48PPM (mg/L CaCO3)
Clark Degrees
3.4° Clark
French Scale
4.8°fH
German Scale
2.7°dH

Exeter tap water is soft and refreshing, averaging 48 PPM. South West Water sources the city's supply from surface water reservoirs fed by the River Exe and River Dart, draining the sandstone and shale moorlands of Exmoor and Dartmoor. With very low dissolved calcium content, Exeter residents enjoy clean, scale-free kettles, shiny chrome taps, and silky lather from soaps and shampoos, without the ongoing expense of water softeners.

76% softer than the UK national baseline (200 PPM)

Neighbourhood Hydro-Variance

Water hardness across Exeter varies by up to 33 PPM between different treatment zones and boreholes.

Softest District35 PPM
St Leonards & Topsham
Hardest District68 PPM
Pinhoe & Whipton
Supplied by South West Water under Drinking Water Inspectorate (DWI) regulatory standards.
Local Installer Quote Network

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Which?-Style Practical Household Advice

Living with Exeter Tap Water: Essential Household Guide

Practical calibrations for kitchen appliances, heating systems, and personal care tailored specifically to Exeter's water profile.

Kettles & Hot Drinks

Virtually never required. A light rinse every 4–6 months clears natural dust and loose sediment.

💡 Pro Tip: Buy food-grade citric acid powder (£5/kg) instead of chemical descaling tablets. One boiled tablespoon cleans the base in 5 minutes with zero lingering odor.
Dishwasher Salt Calibration

Level 0 or 1 (Minimum). Multi-benefit all-in-one tablets supply all conditioning needed.

⚙️ Recommended Dial Setting: Level 1 / Off (refer to machine manual).
Boiler Efficiency & BS 7593

Zero mineral scale drag on combi boiler heat exchangers. Maintain system corrosion inhibitor under BS 7593.

🛡️ Compliance: British Standard BS 7593 requires regular chemical inhibitor dosing and annual testing to prevent heat exchanger scale drag.
Bathing, Hair & Sensitive Skin

Soaps and shampoos lather effortlessly with tiny amounts. Kind to sensitive skin and eczema sufferers.

🚿 Shower Screens: Use a rubber squeegee after each shower to prevent dissolved calcium from baking into the glass under hot steam.
Common Questions

Frequently Asked Questions about Exeter Tap Water

Is Exeter tap water hard or soft?
Exeter tap water is soft, with an average hardness of 48 PPM (3.4 Clark degrees). It flows from clean moorland rivers across Devon and Somerset.
Do I need dishwasher salt in Exeter?
Dishwasher salt is optional or can be set to Level 1 in Exeter due to the low mineral content of the water.
Does Exeter water cause limescale in kettles?
No, limescale accumulation in Exeter kettles is negligible, requiring only light rinsing to remove natural loose sediment.
WaterHardness.uk Technical & Water Quality Research Team
Data sourced from South West Water compliance reports and Drinking Water Inspectorate (DWI) public records.