Side-by-Side Water Hardness Calculator

Compare Water Hardness Between Areas

Analyze real-time PPM, Clark degrees, limescale risk, and dishwasher salt settings between any two UK postcode sectors.

Water Quality Comparison Analysis

Executive Summary: Sector GU21 3 vs Sector SW1A 1

Comparing tap water mineral concentration between Sector GU21 3 (Affinity Water) and Sector SW1A 1 (Thames Water) reveals a water hardness difference of 30 PPM. Sector SW1A 1 has softer water at 275 PPM (Hard) compared to Sector GU21 3 at 305 PPM (Very Hard).

Limescale risk and boiler heating efficiency vary based on these mineral levels. Households in Sector GU21 3 experience higher heating element degradation and kettle scale accumulation due to elevated calcium carbonate density (305 PPM vs 275 PPM).

For home appliance setup, Bosch dishwasher water softener settings should be calibrated accordingly: Sector GU21 3 requires setting H06 / H07 whereas Sector SW1A 1 recommends setting H04.

NP

Sector SW1A 1 has 30 PPM LOWER water hardness than Sector GU21 3

Lower PPM indicates softer water, reduced limescale risk, and lower detergent usage.

Water Metric
Sector GU21 3Outcode: GU21
Sector SW1A 1Outcode: SW1A
Hardness (PPM)
305 PPM
275 PPM
Clark Degrees
21.3 °Clark
19.3 °Clark
Classification
Very Hard
Hard
Bosch Salt Setting
H06 / H07
H04
Water Supplier
Affinity Water
Thames Water
Postcodes Covered
166 postcodes
66 postcodes