Executive Summary: Sector CH5 4 vs Sector SW1A 1
Comparing tap water mineral concentration between Sector CH5 4 (Severn Trent / Hafren Dyfrdwy) and Sector SW1A 1 (Thames Water) reveals a water hardness difference of 125 PPM. Sector CH5 4 has softer water at 150 PPM (Moderately Hard) compared to Sector SW1A 1 at 275 PPM (Hard).
Limescale risk and boiler heating efficiency vary based on these mineral levels. Households in Sector SW1A 1 experience higher heating element degradation and kettle scale accumulation due to elevated calcium carbonate density (275 PPM vs 150 PPM).
For home appliance setup, Bosch dishwasher water softener settings should be calibrated accordingly: Sector CH5 4 requires setting H02 whereas Sector SW1A 1 recommends setting H04.