UK Water Quality Report • 2026 Data

Water Hardness in DA4

Water supply analysis across 2 postcode sectors in DA4 (Thames Water).

Outcode Avg Hardness275 PPMHard Water
Regional Quality Overview

Water Supply Analysis: Outcode DA4

Looking for water hardness metrics in DA4? 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 DA4. The lowest mineral concentration is recorded in sector DA4 0 at 275 PPM, whereas sector DA4 9 experiences higher mineral levels reaching 275 PPM.

Due to the hard water (275 PPM) in DA4, 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 DA4

Lowest mineral concentration

Softest
Sector DA4 0105 Postcodes • Hard
275 PPM19.3 °Clark

Hardest Sector in DA4

Highest mineral concentration

Highest Hardness
Sector DA4 9138 Postcodes • Hard
275 PPM19.3 °Clark

All Postcode Sectors in DA4

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