Annfield Plain Water Hardness & Quality Report (2026)

Northumbrian Water supplies Annfield Plain, the former mining village in north-west County Durham near Stanley — a plateau community at around 250 metres above sea level on the Durham Coal Measures, with a typical north Durham colliery village character of terraced streets and community clubs, part of the post-industrial landscape between Consett and the Stanley/Chester-le-Street corridor — from Derwent Reservoir in the north Pennine upland above the Derwent Valley near Consett, treated at Mosswood Water Treatment Works near Ebchester. At 74.5 mg/L (5.2°Clark), Annfield Plain's water is soft — consistent with the impermeable Carboniferous Millstone Grit and Coal Measures upland catchment of the north Pennines above the Derwent that contributes very little calcium to the reservoir supply.

Annfield Plain lies in the County Durham Coal Measures plateau where Northumbrian Water delivers supply from Derwent Reservoir on the north Pennine Millstone Grit upland above Consett. The Carboniferous Millstone Grit and peat moorland catchment yields very low mineralisation soft water, producing 74.5 mg/L with TDS 168.3 mg/L — soft water characteristic of the Northumbrian Water north-west Durham distribution zone at Consett (74 mg/L) and Stanley in the same Derwent Reservoir supply corridor.

At 74.5 mg/L, limescale is a minimal household concern in Annfield Plain. Kettle descaling every two to three months is typically all that is required. The combi-boiler has very low scaling risk. Washing-up liquid lathers readily with small quantities. Taps and shower heads accumulate very little limescale; a quarterly wipe keeps fixtures clean. Annfield Plain's soft supply reflects the north Durham upland geology — the impermeable Millstone Grit and Coal Measures of the north Pennine plateau providing soft, low-mineralisation water to the coal-country communities of north-west Durham, where the pit villages were built on gritstone moorland that keeps its rain clean and soft.