Hard Water

Check the water in your area

Use our simple postcode checker to quickly find the hardness of the water in your area.

What is hard water?

Hard water is water that has high levels of calcium and magnesium compounds. Whilst not harmful to humans in drinking water, these compounds solidify when the water is heated, leaving limescale build up on surfaces.

This is most obvious on taps, shower heads and other fittings, but limescale can occur wherever hard water is heated. This can be inside pipework, on the heating element of dishwashers, washing machines, inside domestic kettles or commercial wall mounted kettles. Limescale can also wreak havoc in hot water systems and heating systems.

How do I know if I have hard water?

Roughly 65% of the UK is supplied with mains water that is classified as hard, as shown on this map. If you haven’t already done so, enter your postcode above to get a reading for your local water hardness.

Tell-tale signs include frequent breakdown of equipment that heats water, boilers that are noisy when firing, poor water pressure, and crusty build up around fixtures and fittings.

The hidden cost of limescale

Many householders and facility managers don’t realise that they are paying more as a result of their hard water. Limescale can be expensive in a number of ways:

  1. Repair or replacement of appliances: In hard water areas, shower heads and kettles need replacing more often. Appliances also tend to break down sooner than expected.
  2. Energy costs: Just 1.6mm of limescale build up can cause a 12% drop in heat transfer efficiency, meaning that equipment has to work harder to heat water up.
  3. Prevention costs: Whilst protecting against the build up of limescale is cheaper than the costs of not protecting against it, certain methods can be costly to maintain.

Battling limescale with softeners

Sentinel Sumo is a high efficiency, non-electric water softener that fits perfectly on the sink (H x W x D) 492 x 235 x 475mm. It regenerates in as quick as 11 minutes and it is the perfect solution to protect fittings and appliances against scaling in hard water areas.


Battling limescale with Electrolytic devices

Sentinel SESI delivers no-fuss protection and pays for itself in 3-6 months in terms of energy bill savings. For commercial or non-domestic buildings, Sentinel KalGUARD comes in a wide range of sizes and can deliver an ROI in as little as 12 months.

- Independently proven
- Ccost effective
- Low maintenance
- Recommended in the Building Regulations Compliance Guide

15mm SESI                                              22mm SESI