UK Water Quality Report • 2026 Data

Water Hardness in SP11

Water supply analysis across 5 postcode sectors in SP11 (Southern Water).

Outcode Avg Hardness282 PPMHard Water
Regional Quality Overview

Water Supply Analysis: Outcode SP11

Analyzing water quality disclosures across all 5 postcode sectors in outcode SP11 reveals an average water hardness of 282 PPM (Hard Water). Public water supply across this area is managed by Southern Water, responsible for treating and delivering water to residential households.

Water chemistry can fluctuate across supply zones in SP11. The lowest mineral concentration is recorded in sector SP11 0 at 280 PPM, whereas sector SP11 9 experiences higher mineral levels reaching 290 PPM.

Due to the hard water (282 PPM) in SP11, 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 SP11

Lowest mineral concentration

Softest
Sector SP11 0218 Postcodes • Hard
280 PPM19.6 °Clark

Hardest Sector in SP11

Highest mineral concentration

Highest Hardness
Sector SP11 9290 Postcodes • Hard
290 PPM20.3 °Clark

All Postcode Sectors in SP11

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