Bartley Green Water Hardness & Quality Report (2026)

Bartley Green, the west Birmingham suburb adjacent to the Bartley Reservoir near Frankley in the City of Birmingham, is supplied by Severn Trent Water primarily from the Elan Valley Aqueduct. The 118 km Elan Valley Aqueduct transports exceptionally soft water from the Elan and Claerwen Reservoirs in the Cambrian mountains of mid-Wales to Frankley Water Treatment Works in south-west Birmingham — one of the largest water treatment works in the UK, located practically on Bartley Green's doorstep. The Elan Valley catchment drains ancient Ordovician and Silurian greywacke, mudstone and quartzite — calcium-depleted Welsh upland rocks generating very soft water at 30–50 mg/L at source. By the time this soft Welsh water is distributed through the Birmingham network to Bartley Green, limited blending with local groundwater and mineral exchange in the distribution network elevates hardness to 130 mg/L. The TDS of 306.4 mg/L (ratio 2.36) is consistent with a predominantly soft Welsh surface-water supply with modest mineral enrichment.

The Elan and Claerwen Reservoirs in the Cambrian mountains drain metamorphic and sedimentary Palaeozoic rocks with virtually no calcium carbonate content — the purest large upland supply system in Wales. The elevation of supply hardness from 40–50 mg/L at source to 130 mg/L in west Birmingham reflects gradual mineral exchange within Birmingham's large distribution network and possible blending with harder groundwater from Triassic Sherwood Sandstone boreholes in the east Birmingham supply zone. Bartley Green, being closest to the Frankley WTW, receives a higher proportion of the soft Elan water than east Birmingham suburbs that receive more blended supply.

At 130 mg/L Bartley Green's water is moderately soft and limescale accumulation is manageable. Kettles benefit from descaling every six to eight weeks with a citric acid tablet. Shower screens develop modest spotting. Washing-up liquid lathers well. Combi-boilers face low to moderate scaling risk. Bartley Green's pleasant suburban character — semi-detached housing, school playing fields and the reservoir wooded fringe — benefits from the western bias of Birmingham's Elan Valley supply, producing a noticeably softer supply than east or central Birmingham's Triassic-groundwater-enriched zones.