Godalming Water Hardness & Quality Report (2026)

Godalming, the historic Surrey town on the River Wey south of Guildford — the site of the world's first public supply of electricity — is supplied by South East Water from the North Downs Chalk Aquifer and the Upper Greensand aquifer of the Surrey hills. South East Water operates chalk and greensand boreholes in the North Downs escarpment and dip slope north of Godalming, and in the Upper Greensand (Hythe and Folkestone Beds) that outcrop along the base of the North Downs scarp. The chalk boreholes tap the Cretaceous Upper Chalk between the North Downs crest and the Greensand foothills, distributing treated supply to the Wey valley and south Surrey lowland from Guildford Water Treatment Works and local borehole sources. At 270.5 mg/L with TDS 729.4 mg/L, Godalming's supply is very hard — harder than the Thames-surface-water-dominant London zones and harder than north-east Kent chalk zones, reflecting the concentrated quality of North Downs chalk borehole groundwater with limited surface-water dilution.

The Cretaceous Chalk of the North Downs in the Guildford–Godalming sector is the Upper Chalk (Turonian–Campanian), dipping gently north-east away from the North Downs scarp. Chalk groundwater at 40–80 m depth achieves calcium bicarbonate hardness of 260–280 mg/L in the semi-confined zones beneath the Weald Clay at the southern flank of the North Downs. The Upper Greensand aquifer contributes additional hardness from calcareous sandstone dissolution, and the TDS of 729.4 mg/L (ratio 2.70) indicates sulphate from Hythe Beds calcareous cement and Upper Chalk flint formation water.

At 270.5 mg/L Godalming's water is very hard. Kettle elements accumulate limescale rapidly — fortnightly descaling with citric acid is the minimum requirement. Shower screens develop a dense calcium deposit without weekly chemical treatment. Washing-up liquid produces poor lather without generous use. Combi-boilers need inline magnetic scale inhibitors and regular professional servicing. Godalming's handsome Surrey character — Charterhouse, the Wey towpath and the Arts and Crafts heartland of south Surrey — is served by one of the hardest water supplies in the home counties, where the North Downs chalk geology shapes both the distinctive chalk downland landscape and the domestic limescale challenge.