UK Water Quality Report • 2026 Data

Water Hardness in SL7

Water supply analysis across 4 postcode sectors in SL7 (Thames Water).

Outcode Avg Hardness275 PPMHard Water
Regional Quality Overview

Water Supply Analysis: Outcode SL7

For residents and businesses in outcode SL7, understanding local water chemistry is essential for appliance longevity and limescale prevention. Our environmental data shows that SL7 averages 275 PPM in mineral content, falling into the Hard Water classification.

Water chemistry can fluctuate across supply zones in SL7. The lowest mineral concentration is recorded in sector SL7 1 at 275 PPM, whereas sector SL7 9 experiences higher mineral levels reaching 275 PPM.

Due to the hard water (275 PPM) in SL7, 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 SL7

Lowest mineral concentration

Softest
Sector SL7 1264 Postcodes • Hard
275 PPM19.3 °Clark

Hardest Sector in SL7

Highest mineral concentration

Highest Hardness
Sector SL7 96 Postcodes • Hard
275 PPM19.3 °Clark

All Postcode Sectors in SL7

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