UK Water Quality Report • 2026 Data

Water Hardness in TW5

Water supply analysis across 2 postcode sectors in TW5 (Thames Water).

Outcode Avg Hardness275 PPMHard Water
Regional Quality Overview

Water Supply Analysis: Outcode TW5

Looking for water hardness metrics in TW5? Water supplied by Thames Water in this outcode registers a baseline average of 275 PPM across 2 distinct postcode sectors.

Water chemistry can fluctuate across supply zones in TW5. The lowest mineral concentration is recorded in sector TW5 0 at 275 PPM, whereas sector TW5 9 experiences higher mineral levels reaching 275 PPM.

Due to the hard water (275 PPM) in TW5, 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 TW5

Lowest mineral concentration

Softest
Sector TW5 0185 Postcodes • Hard
275 PPM19.3 °Clark

Hardest Sector in TW5

Highest mineral concentration

Highest Hardness
Sector TW5 9215 Postcodes • Hard
275 PPM19.3 °Clark

All Postcode Sectors in TW5

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