The Effects of Hard Water on Your Commercial / Industrial Equipment

Around 60% of the UK is classed as having hard or very hard water. In a home, the effects are visible and annoying. In a commercial kitchen, bar or laundry, hard water can shorten equipment life, push up energy bills and spoil cleaning results.

This guide explains what hard water is, how to check whether your area is affected, and what you can do to protect your commercial dishwashers, glasswashers and laundry equipment.

What Causes Hard Water?

Water hardness is the amount of dissolved calcium and magnesium in the water. Hard water is found in areas of the UK where the bedrock is made up of sedimentary rocks such as limestone, chalk, flint and sandstone. The South East is mostly chalk and limestone, which is why it has the hardest water in the country. When those minerals come out of the water and harden on surfaces, we call it limescale.

Understanding Water Hardness Levels

Water hardness is usually measured in parts per million (ppm) of calcium carbonate:

Is Your Area Affected? UK Counties With the Hardest Water

Based on data from regional water suppliers, these are some of the worst-affected counties in the UK:

• Bedfordshire (300+ ppm)
• Buckinghamshire (300+ ppm)
• Dorset (300+ ppm)
• Essex (300+ ppm)
• Hampshire (300+ ppm)
• Hertfordshire (300+ ppm)
• Kent (300+ ppm)
• Oxfordshire (300+ ppm)
• Surrey (300+ ppm)
• Sussex (300+ ppm)
• Wiltshire (300+ ppm)
• Gloucestershire (200+ ppm)

Hardness can vary within a county, so it's always worth checking your exact postcode.

How to Check the Water Hardness at Your Premises

• Postcode checker: Enter your postcode on your water supplier's website, for example Thames Water, Anglian Water, Affinity Water or Severn Trent. Most show your hardness in ppm or mg/l.
• Test strips: Water hardness test strips give a quick reading from the tap. Many commercial dishwasher and softener suppliers include them at installation.
• Soap test: Shake some water with a few drops of liquid soap in a jar. If you get only a few bubbles and the water turns cloudy, your water is hard.

Knowing your reading matters because it tells you how to set your dishwasher's built-in softener and which water treatment you need.

The Impact of Hard Water on Commercial Equipment

Hard water can reduce the lifespan of industrial and commercial equipment. Minerals are deposited on every surface they touch, including heating elements, boilers, pipework, spray arms and valves. The build-up makes equipment less efficient and raises energy costs, because heaters have to work through a layer of scale. Hard water can also damage linen, etch glass, bind with detergents to cause odours, and leave chalky residue or spots on dishes.

You can periodically flush the system and replace the water in the boiler to maintain equipment, but this uses more water, energy and chemicals, so it is money going down the drain.

Hard Water and Commercial Dishwashers & Glasswashers

Warewashing equipment is among the hardest-hit in any hard-water area. Water is heated to high temperatures on every cycle, which speeds up limescale formation on elements, in the boiler and around the rinse jets. Common signs include:

• White spots, streaks or a cloudy film on glasses and plates
• Blocked or partially blocked spray and rinse arms
• Longer cycle times or water that doesn't reach temperature
• Higher detergent and rinse-aid consumption
• More frequent breakdowns and element failures

How to Protect Commercial Dishwashers From Hard Water

Install a water softener or choose a machine with one built in. Many commercial dishwashers and glasswashers can be supplied with an integrated softener that treats incoming water before it enters the wash chamber. For very hard areas or high-volume sites, an external softener or reverse osmosis unit may be the better option.

Use the correct chemicals and salt. The right detergent, rinse aid and dishwasher salt make a big difference to results in hard-water areas. Salt is what regenerates a built-in softener, so it needs topping up regularly.

Descale and maintain regularly. Routine descaling and filter cleaning prevent build-up. In hard-water areas, minerals build up faster, so maintenance should be more frequent.

Choose hard-water-friendly models. When replacing equipment, look for machines designed to operate in hard-water conditions, such as models with built-in softeners, break tanks or scale-resistant elements. 

Water Softening Technologies Explained

The best way to reduce the effects of hard water across all your equipment is to treat the water supply itself. The two most common methods are ion exchange and reverse osmosis.

Ion exchange swaps calcium, magnesium and other minerals for sodium ions, which softens the water. This is how most built-in and external commercial softeners work.

Reverse osmosis uses pressure to force water through a semipermeable membrane that catches the minerals and contaminants and filters them out. It's often used for glasswashers where a spot-free, polish-free finish is a priority.

Removing minerals from the supply reduces maintenance and repairs caused by corrosion and blockages. It also keeps machines running efficiently, which lowers energy costs.

Things to Consider

• The hardness level at your premises (check your postcode first)
• Which equipment needs treated water: dishwashers, glasswashers, washing machines, combi ovens or coffee machines
• Upfront cost, as some water-softening technologies need significant investment
• Whether professional installation is needed

Frequently Asked Questions

Which part of the UK has the hardest water?

The South and East of England, especially the South East, London and the Home Counties, where chalk and limestone bedrock is common. Many counties here have readings above 300 ppm.

Do I need a water softener for a commercial dishwasher?

In moderately hard to very hard areas, many manufacturers recommend water treatment. Without it, you're likely to see poorer results and more frequent repairs. Check your manufacturer's guidance, as running without treatment in a hard-water area may affect your warranty.

How often should I descale a commercial dishwasher?

It depends on your water hardness and how heavily the machine is used. In hard-water areas without a softener, monthly or even more frequent descaling may be needed.

Protect Your Equipment From Hard Water

Hard water is a fact of life across much of the UK, and it's a real threat to businesses that use a lot of water every day. A little limescale may seem minor at first, but over time it leads to significant damage, wasted energy and costly repairs. With the right equipment, water treatment and maintenance, you can protect your investment and keep your dishwashers, glasswashers and laundry machines running efficiently.

Need help choosing the right solution for your premises? Contact the GA Commercial team to discuss your water hardness and find equipment suited to your site.