The 35 supply zones South Staffordshire Water publishes a hardness figure for runs 136.3–351.8 mg/L as CaCO₃, varying by supply zone, which spans DWI's Slightly hard to Very hard bands, per South Staffordshire Water — supply-zone water quality reports (31 December 2025, read 20 September 2026).
Source: South Staffordshire Water — supply-zone water quality reports — dated 31 December 2025, read 20 September 2026
Drinking Water Inspectorate (DWI) enforces the UK drinking water quality regulations in England and Wales. Figures it classifies or regulates on this page cover England and Wales only.