UK water hardness checker

Check your water hardness by postcode

Get accurate water hardness data for your area using water supply zone information.

Uses water supply zone data for more accurate results

What is water hardness?

Water hardness is caused by naturally occurring minerals, mainly calcium and magnesium. It is measured in parts per million of calcium carbonate.

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Problems caused by hard water

Hard water can lead to limescale buildup, reduced appliance efficiency, higher energy bills, and dry skin or hair.

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How to reduce limescale

The right filtration or softening solution can protect your home, appliances, and family from the effects of hard water.

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How hard water affects your home and family

Limescale buildup

Leaves deposits in kettles, taps, showers, and pipes, reducing flow and lifespan.

Reduced appliance efficiency

Limescale makes appliances work harder, using more energy and increasing running costs.

Soap scum and dull surfaces

Hard water makes it difficult to get a lather, leaving soap scum on surfaces and bathrooms.

Dry skin and hair

Hard water can leave skin feeling dry and hair looking dull or difficult to manage.

Frequently asked questions

What is ppm calcium carbonate?

It is the standard way of expressing hardness as milligrams per litre of calcium carbonate, usually shown as ppm.

Who supplies my water?

Your supplier depends on your postcode and water supply zone. The checker displays the best available company data.

Why can hardness vary by area?

Neighbouring postcodes can draw water from different supply zones, reservoirs, or boreholes, so hardness can vary locally.

Do I need a water softener or filter?

A softener removes hardness minerals. A limescale filter or whole house system can inhibit scale and improve water quality with less maintenance.

Recommended solutions

Protect your home from limescale and enjoy better water every day.

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Whole house water treatment system Whole house systemsComplete protection for your home and family. Aqua Prime antiscale shower filter Shower filtersImprove shower water feel and help reduce chlorine, sediment and scale-related buildup. Under sink water filter system Filter systemsBrowse under-sink, inline and point-of-use systems for taste, chlorine and sediment reduction.