Market Harborough Water Hardness & Quality Report (2026)

Market Harborough, the south Leicestershire market town on the River Welland at the Northamptonshire border — famous for its canal, grammar school and hunting country — is supplied by Severn Trent Water from the Jurassic Limestone Aquifer of south Leicestershire and north Northamptonshire. Boreholes in the south Leicestershire plateau tap the Jurassic Lincolnshire Limestone and Northampton Sand (Inferior Oolite) — productive water-bearing carbonate rock horizons that underlie the limestone ridge country south-east of Market Harborough. Severn Trent also draws on the Welland valley abstraction and distributes from the east Midlands supply network. Market Harborough is harder than Melton Mowbray (190.5 mg/L) to the north, reflecting a greater proportion of the harder south Leicestershire Jurassic oolite groundwater in its supply blend. The TDS of 560.9 mg/L reflects Jurassic carbonate groundwater with sulphate contributions from Lias Clay interbeds.

The Jurassic Lincolnshire Limestone and Northampton Sand that form the limestone escarpment south-east of Market Harborough are the same oolitic and calcareous limestone formations that extend north through Lincolnshire and south through Northamptonshire. These productive carbonate aquifers dissolve calcium and magnesium bicarbonate into percolating groundwater over months to years of subsurface residence, producing hardness at 200–220 mg/L in the south Leicestershire–north Northamptonshire supply zone. The Lias Clay interbeds below the Jurassic oolite contribute minor sulphate and sodium to the groundwater, elevating TDS above purely carbonate-hardness-based values.

At 212.5 mg/L Market Harborough's water is hard and limescale is a consistent domestic concern. Kettles benefit from monthly descaling with a dedicated citric acid tablet. Shower screens and tile grout develop a white calcium film requiring regular treatment with white vinegar. Washing-up liquid must be used generously. Combi-boilers benefit from inline scale inhibitor protection and regular servicing. Market Harborough's identity as a Leicestershire hunting town in the Jurassic limestone country — the Fernie and the Pytchley hunt meets — is reflected in its moderately hard limestone-fed domestic water supply.