UK Water Quality Report • 2026 Data

Water Hardness in SN38

Water supply analysis across 10 postcode sectors in SN38 (Thames Water).

Outcode Avg Hardness275 PPMHard Water
Regional Quality Overview

Water Supply Analysis: Outcode SN38

For residents and businesses in outcode SN38, understanding local water chemistry is essential for appliance longevity and limescale prevention. Our environmental data shows that SN38 averages 275 PPM in mineral content, falling into the Hard Water classification.

Water chemistry can fluctuate across supply zones in SN38. The lowest mineral concentration is recorded in sector SN38 0 at 275 PPM, whereas sector SN38 9 experiences higher mineral levels reaching 275 PPM.

Due to the hard water (275 PPM) in SN38, 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 SN38

Lowest mineral concentration

Softest
Sector SN38 02 Postcodes • Hard
275 PPM19.3 °Clark

Hardest Sector in SN38

Highest mineral concentration

Highest Hardness
Sector SN38 91 Postcodes • Hard
275 PPM19.3 °Clark

All Postcode Sectors in SN38

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