UK Water Quality Report • 2026 Data

Water Hardness in SE4

Water supply analysis across 3 postcode sectors in SE4 (Thames Water).

Outcode Avg Hardness275 PPMHard Water
Regional Quality Overview

Water Supply Analysis: Outcode SE4

Analyzing water quality disclosures across all 3 postcode sectors in outcode SE4 reveals an average water hardness of 275 PPM (Hard Water). Public water supply across this area is managed by Thames Water, responsible for treating and delivering water to residential households.

Water chemistry can fluctuate across supply zones in SE4. The lowest mineral concentration is recorded in sector SE4 1 at 275 PPM, whereas sector SE4 9 experiences higher mineral levels reaching 275 PPM.

Due to the hard water (275 PPM) in SE4, 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 SE4

Lowest mineral concentration

Softest
Sector SE4 1245 Postcodes • Hard
275 PPM19.3 °Clark

Hardest Sector in SE4

Highest mineral concentration

Highest Hardness
Sector SE4 911 Postcodes • Hard
275 PPM19.3 °Clark

All Postcode Sectors in SE4

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