UK Water Quality Report • 2026 Data

Water Hardness in CO3

Water supply analysis across 5 postcode sectors in CO3 (Anglian Water).

Outcode Avg Hardness310 PPMVery Hard Water
Regional Quality Overview

Water Supply Analysis: Outcode CO3

Looking for water hardness metrics in CO3? Water supplied by Anglian Water in this outcode registers a baseline average of 310 PPM across 5 distinct postcode sectors.

Water chemistry can fluctuate across supply zones in CO3. The lowest mineral concentration is recorded in sector CO3 0 at 310 PPM, whereas sector CO3 9 experiences higher mineral levels reaching 310 PPM.

Due to the very hard water (310 PPM) in CO3, limescale build-up can occur on heating elements, shower heads, and boilers. Setting your dishwasher water softener to the correct level (e.g. Bosch setting H07 (Max Salt)) is strongly recommended to prevent cloudy glassware and internal scale accumulation. Review the individual postcode sectors below to get precise dishwasher salt settings and limescale recommendations.

Softest Sector in CO3

Lowest mineral concentration

Softest
Sector CO3 0205 Postcodes • Very Hard
310 PPM21.7 °Clark

Hardest Sector in CO3

Highest mineral concentration

Highest Hardness
Sector CO3 9148 Postcodes • Very Hard
310 PPM21.7 °Clark

All Postcode Sectors in CO3

Select a postcode sector below to view exact water softener salt settings, limescale protection guides, and appliance recommendations.