Formby Water Hardness & Quality Report (2026)

Formby, the Sefton Borough town on the Lancashire coast between Crosby and Southport known for its red squirrel woods and coastal dunes, is served by United Utilities. Supply draws on soft Lake District water via the Thirlmere and Haweswater Aqueducts, blended with local groundwater from the Permo-Triassic Sherwood Sandstone aquifer of the Sefton coastal plain. The Formby supply zone incorporates a higher proportion of Triassic sandstone groundwater than the adjacent Maghull zone (128.5 mg/L) to the east — reflecting Formby's position on the coastal dune plain directly above productive Bunter Sandstone boreholes that supply additional groundwater to the Sefton distribution grid. The elevated TDS of 506.4 mg/L for a hardness of 171.5 mg/L (ratio 2.95) confirms a significant calcium sulphate contribution from Keuper Marl evaporite interbeds in the Triassic sandstone sub-surface — the same Triassic evaporite signature seen throughout the west Lancashire supply zone.

The Permo-Triassic Sherwood Sandstone beneath the Sefton coastal plain is one of the most productive aquifer horizons in north-west England — a coarse red sandstone with calcium-carbonate and calcium-sulphate cement and interbedded Keuper Marl evaporite beds. Groundwater in this formation at 50–100 m depth carries moderately hard, sulphate-enriched water at 160–180 mg/L. United Utilities blends this with soft Thirlmere and Haweswater supply to produce Formby's 171.5 mg/L hardness — moderately hard, and considerably harder than Maghull's more aqueduct-dominant 128.5 mg/L.

At 171.5 mg/L Formby's water is moderately hard and limescale management is a regular domestic task. Kettles benefit from descaling every four to five weeks with a citric acid tablet. Shower heads need periodic soaking in white vinegar to maintain clear jets. Washing-up liquid lathers adequately. Combi-boilers benefit from inline scale inhibitor protection. Formby's attractive coastal character — the National Trust pinewoods, the red squirrel reserve and the wide dune beaches — is complemented by the moderately hard Triassic sandstone water from the same coastal plain that formed the dunes.