UK Water Quality Report • 2026 Data

Water Hardness in W4

Water supply analysis across 6 postcode sectors in W4 (Thames Water).

Outcode Avg Hardness275 PPMHard Water
Regional Quality Overview

Water Supply Analysis: Outcode W4

For residents and businesses in outcode W4, understanding local water chemistry is essential for appliance longevity and limescale prevention. Our environmental data shows that W4 averages 275 PPM in mineral content, falling into the Hard Water classification.

Water chemistry can fluctuate across supply zones in W4. The lowest mineral concentration is recorded in sector W4 1 at 275 PPM, whereas sector W4 9 experiences higher mineral levels reaching 275 PPM.

Due to the hard water (275 PPM) in W4, 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 H04) 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 W4

Lowest mineral concentration

Softest
Sector W4 1199 Postcodes • Hard
275 PPM19.3 °Clark

Hardest Sector in W4

Highest mineral concentration

Highest Hardness
Sector W4 921 Postcodes • Hard
275 PPM19.3 °Clark

All Postcode Sectors in W4

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