Northamptonshire one of the most likely areas to experience plumbing issues due to hard water

The research, from hard water softener experts, Aspect, looked at the water hardness scores of counties across England, categorising them as having soft, moderately hard, hard, or very hard water.

Northamptonshire comes in fourth place overall, when ranked against the other English counties. It has a water hardness score of 320, placing it in the ‘very hard’ category.

While this isn’t usually a health hazard, the most significant impact that hard water can have is on your plumbing, central heating, and drainage.

Scale can build up anywhere, with the potential to damage both cold and hot systems, including boilers, dishwashers and washing machines - causing corrosion, reduced flow rate and eventually blockages.

The top 20 English counties with the hardest water

County

Water Hardness figure

Category

Kent

343

Very hard

Cambridgeshire

341

Very hard

Gloucestershire

341

Very hard

Northamptonshire

320

Very hard

West Sussex

319

Very hard

Essex

310

Very hard

Bedfordshire

300

Very hard

Warwickshire

300

Very hard

Buckinghamshire

286

Very hard

Norfolk

286

Very hard

Hertfordshire

280

Very hard

Lincolnshire

280

Very hard

Nottinghamshire

280

Very hard

Oxfordshire

280

Very hard

Derbyshire

278

Very hard

Greater London

274

Very hard

Northumberland

274

Very hard

Tyne & Wear

274

Very hard

Dorset

272

Very hard

Shropshire

270

Very hard

The research revealed Kent as the English county with the hardest water, with a score of 343, while Barnet was the London Borough with the hardest water, with a score of 327.

The South East of the UK is mostly made up of chalk and limestone geology, which contributes to these areas having the hardest water in the UK, as it leads to high quantities of calcium and magnesium ions in the water supply.

Of the 32 London Boroughs which were analysed, 9% had hard water, and 91% had very hard water. Meanwhile, of the 49 counties which were analysed, 2% had soft water, 29% had moderately hard water, 24% had hard water, and 46% had very hard water.

Gloucestershire was the UK county with the second hardest water, joint with Cambridgeshire, and followed by Northamptonshire and West Sussex. Of the London Boroughs, Enfield came second, followed by Harrow, Barking and Dagenham, and Kingston upon Thames.

Only one county, Cumbria, was found to have water which was categorised as being soft. This is because this is the area of the country with one of the lowest levels of chalk and limestone in its geology, resulting in a lower calcium and magnesium content in the water supply.

James Hays, Technical Manager of Plumbing, Heating and AC at property maintenance experts Aspect, said: “While hard water isn’t usually a risk to your health, it can have a significant effect on plumbing fixtures, causing corrosion, damage and reduced functionality, and increasing the risk of water leaks.

“The vast majority of us live in hard water areas, where the bedrock is made of sedimentary rocks like limestone, chalk, flint and sandstone. The South East of the UK is mainly made up of chalk and limestone regions and as a result, has the hardest water. This can be seen in the findings of our research, with areas in the South East of the UK, such as Kent, Cambridgeshire, and London, all scoring highly.

“The good news is that there are measures that you can take to help to protect your plumbing fixtures from these issues, ensuring they remain both functional and visually appealing. If you live in an area with hard or very hard water, purchasing a water softener may solve these problems for you, by replacing the hardness in the water with sodium ions. It is essential that you make sure that it is installed by a qualified plumber, to make sure that it is done correctly and safely.”