Fair Oak Water Hardness & Quality Report (2026)

South East Water supplies Fair Oak, the Hampshire village east of Eastleigh in the Eastleigh Borough — a substantial residential community in the south Hampshire countryside, well-positioned between the M3 motorway and the South Downs National Park boundary, with good schools and easy access to both Winchester and Southampton — from the South Downs Chalk (Cretaceous) and Chalk Marl aquifer boreholes in the east Hampshire Winchester–Eastleigh supply zone, treated at Otterbourne Water Treatment Works near Winchester. At 304 mg/L (21.3°Clark) and a TDS of 904.3 mg/L, Fair Oak's water is extremely hard with an elevated TDS/hardness ratio (2.97) — reflecting very high calcium carbonate from the Upper Chalk and significant sulphate from the Upper Greensand (Selbornian) and Gault Clay beneath the chalk in the east Hampshire supply zone.

Fair Oak lies in the east Hampshire chalk belt in the South East Water supply zone drawing from deep South Downs Chalk boreholes. The thick Upper Chalk aquifer delivers highly concentrated calcium carbonate, while the underlying Upper Greensand (glauconitic sand and limestone) and Gault Clay contribute significant sulphate, producing 304 mg/L with TDS 904.3 mg/L — extremely hard water with a near-3.0 TDS/hardness ratio characteristic of the deep South Downs chalk and Greensand supply zone at Winchester (302 mg/L), Chandler's Ford, and Eastleigh in the same east Hampshire distribution corridor.

At 304 mg/L, limescale is a severe and relentless household problem in Fair Oak. Kettles should be descaled every week. The combi-boiler requires a fitted scale inhibitor and annual professional servicing as an absolute minimum. Washing-up liquid requires very generous quantities. Taps and shower heads develop heavy chalk deposits within days; frequent descaling with white vinegar or a proprietary product is essential. A whole-house water softener is strongly recommended for Fair Oak households — at 304 mg/L with TDS approaching 1,000 mg/L, the east Hampshire chalk supply is one of the hardest in England, and protecting appliances from limescale will extend their useful life significantly.