Tredegar Water Hardness & Quality Report (2026)

Dŵr Cymru Welsh Water supplies Tredegar, the birthplace of Aneurin Bevan and an iconic town of the South Wales Valleys in Blaenau Gwent, from upland reservoirs in the Sirhowy Valley catchment and the South Wales Coalfield plateau above the town, treated at regional Blaenau Gwent works before distribution. At 110 mg/L (7.7°Clark), Tredegar's water is moderately soft, consistent with the upland Coalfield reservoir supply that characterises communities throughout the South Wales Valleys — a supply shaped by the Millstone Grit and Lower Coal Measures geology of the Sirhowy uplands.

The high moorland above Tredegar drains Millstone Grit (Lower Carboniferous sandstone and shale) — a hard, acid-resistant rock with low calcium solubility producing naturally soft, slightly peaty water. Minor contributions from thin Carboniferous Limestone bands at the valley margins provide a modest calcium increment above the highest-upland baseline. The resulting 110 mg/L with TDS 233.2 mg/L is the classic character of South Wales industrial valley reservoir supply — clean, moderately soft, and very different from the chalk-dominated hard waters of southern England.

At 110 mg/L, Tredegar's water is moderately soft and comfortable for domestic use. Descaling the kettle every six to eight weeks is typically adequate. The combi-boiler benefits from a standard scale inhibitor as a sensible precaution. Washing-up liquid lathers well at everyday quantities. Taps and shower heads develop only light limescale deposits over several weeks; a monthly wipe with white vinegar keeps fixtures in good condition. The clean upland reservoir supply that has served the Sirhowy Valley since the Victorian mining era continues to provide good-quality, soft water to Tredegar's communities.