UK Water Quality Report • 2026 Data

Water Hardness in SW11

Water supply analysis across 9 postcode sectors in SW11 (Thames Water).

Outcode Avg Hardness275 PPMHard Water
Regional Quality Overview

Water Supply Analysis: Outcode SW11

For residents and businesses in outcode SW11, understanding local water chemistry is essential for appliance longevity and limescale prevention. Our environmental data shows that SW11 averages 275 PPM in mineral content, falling into the Hard Water classification.

Water chemistry can fluctuate across supply zones in SW11. The lowest mineral concentration is recorded in sector SW11 1 at 275 PPM, whereas sector SW11 9 experiences higher mineral levels reaching 275 PPM.

Due to the hard water (275 PPM) in SW11, 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 SW11

Lowest mineral concentration

Softest
Sector SW11 1186 Postcodes • Hard
275 PPM19.3 °Clark

Hardest Sector in SW11

Highest mineral concentration

Highest Hardness
Sector SW11 947 Postcodes • Hard
275 PPM19.3 °Clark

All Postcode Sectors in SW11

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