Strood Water Hardness & Quality Report (2026)

Strood, in the Medway unitary authority on the west bank of the River Medway opposite Rochester, is supplied by South East Water from the North Downs Chalk Aquifer and the River Medway chalk catchment of north Kent. South East Water draws from chalk boreholes in the Cretaceous Chalk of the Kent North Downs escarpment north of Strood — the same chalk belt that produces extremely hard water at Tonbridge (310.5 mg/L) in the upper Medway. The Medway at Strood has collected chalk-stream calcium from the North Downs chalk tributaries. While the North Downs chalk in the Medway valley at Strood produces hard water, it is less concentrated than the extreme deep chalk boreholes of the upper Medway valley, giving a lower hardness than Tonbridge but still firmly within the hard range. South East Water distributes to the Medway towns.

Strood's hard water — 219.5 mg/L (15.4°Clark) — reflects the North Downs Chalk Aquifer of the Medway valley in South East Water's north Kent supply zone, harder than many English supply areas but less extreme than the deep chalk boreholes at Tonbridge (310.5 mg/L) further up the Medway. The Drinking Water Inspectorate (DWI) classifies this supply as hard.

Limescale is a persistent household challenge in Strood. At 219.5 mg/L, limescale forms in kettles within two to three weeks and monthly descaling is advisable. Combi-boiler heat exchangers accumulate deposits steadily — annual boiler servicing and an in-line scale inhibitor are recommended. Showerheads, taps, and shower screens develop regular deposits. Washing-up liquid lathers poorly. Using Calgon monthly in the washing machine and maintaining a regular descaling routine is important limescale management for Strood households.