Jarrow Water Hardness & Quality Report (2026)

Jarrow, the South Tyneside town on the south bank of the River Tyne forever associated with the 1936 Jarrow March, is served by Northumbrian Water. Supply to South Tyneside draws on the River Tyne abstracted at Horsley Water Treatment Works near Wylam and supplemented by transfers from Kielder Water via the Tyne–Tees transfer tunnel. The Tyne at this point carries water derived from both Pennine moorland tributaries (the North Tyne draining Northumberland moors) and the South Tyne which flows through the South Pennines and Haydon Bridge area. The elevated TDS of 467.9 mg/L relative to the hardness suggests some contribution from the Magnesian Limestone distribution zone that extends across east County Durham and South Tyneside, where groundwater minerals are picked up within the distribution network.

The Permian Magnesian Limestone runs south-west to north-east beneath the South Tyneside coastal plain, emerging in outcrops at Cleadon and Roker east of Jarrow. Northumbrian Water's distribution network in South Tyneside interconnects zones supplied directly from Kielder/Tyne river water with zones drawing on Magnesian Limestone groundwater further east, and blending between the two occurs through the supply grid. The characteristic calcium–magnesium–sulphate signature of the Magnesian Limestone explains why Jarrow's TDS is substantially higher than its hardness alone would indicate.

At 170 mg/L Jarrow's water is moderately hard and limescale accumulates noticeably over time. Kettles benefit from descaling every four to six weeks — a citric acid soak for 30 minutes is effective. Shower screens and tap nozzles show gradual mineral build-up and should be treated with white vinegar monthly. Washing-up liquid lathers adequately with moderate amounts. Combi-boilers and white goods appliances benefit from inline scale inhibitor protection. Jarrow's predominantly terraced housing stock from the early twentieth century means many homes have older plumbing systems where periodic limescale cleaning of pipe fittings is particularly worthwhile.