Limescale is a problem for many households as much of Britain has hard water, which means it contains deposits of magnesium, calcium or iron salts which adhere to your plumbing. Scotland, Wales and Northern Ireland are less affected than England, but it’s fair to say that the majority of the country is impacted adversely by hard water. For Legionella, these deposits and particles in the water are an excellent source of food, so keeping on top of descaling is an important control measure if your property is in a hard water area.

What is hard water?

Rain water is naturally soft, but when it soaks into the ground it picks up minerals from layers of rock, chalk and limestone as it filters through. These dissolve into the rain water, hardening it and increasing the level of deposits. Water hardness varies throughout the country as the type and concentration of these rock formations is different throughout the landscape. If you’re not sure whether limescale is an issue in your rental property, you can check the hardness of your water online by entering your postcode on websites like this one. The harder the water, the greater problems will be caused by limescale build-up in your system.

Water softeners

There are now many companies out there who can fit a water softener device. These vary in type and size, but are often fitted under the kitchen sink or perhaps in a loft space or garage. Water softener manufacturers claim that their devices save households hundreds of pounds a year as soft water allows heating systems and kitchen appliances to function more efficiently and prolongs their working lives since there is no build-up of scale which can damage their inner workings. If you are renovating a house for rental or buying a new build off-plan, it may be worth looking at the costs and benefits of investing in a water softener.

A word of warning about magnetic water softeners though: the science is unproven as to whether using magnets actually works, and many people say it’s a total con. Our advice would be to do your research thoroughly before making any investment, perhaps using comparison guides and online product reviews to help you decide.

Removing visible limescale

If, however, your property is in a hard water area and you don’t have a water softener fitted, there is still plenty you can do to keep on top of limescale and reduce the risk of Legionella flourishing in your plumbing system.

Limescale is something which accumulates over time and, the greater the build-up, the harder and more laborious the removal of it will be. Therefore, our first tip is to descale regularly (probably at monthly intervals, depending on the hardness of your water). You can even write this into the rental contract as something the tenant needs to do each month.

The most important visible areas to focus on are taps and showerheads as these are where water passes through on its way to making contact with your tenants. The splashing and spraying water can then disperse in the air and be inhaled, potentially carrying Legionella bacteria into the lungs.

There are a number of specialist descaling products available in the supermarket and often it’s just a case of trial and error to see which works best for you. You can also try using citric acid (available from chemists), using 5g of citric acid for every 100ml of water, or even white vinegar (40ml of vinegar to 100ml of water).

To descale a showerhead, immerse the showerhead in the descaling solution and leave it in for the time specified on the product’s instructions. If using citric acid or vinegar, a couple of hours should do the trick. Then remove from the solution, scrub well and rinse thoroughly.

For taps, best practice descaling is to start at the mouth of the tap, scrubbing with descaling solution to remove any deposits around the spout, then work up the tap to clean around the base of it and the handle.

Removing limescale inside the plumbing

In hard water areas no part of your plumbing system will be left untouched by limescale. It’s easy enough to clean it from baths, sinks, showers and kettles, but what about inside your pipes and water tank, the interior of the boiler of any of the other hidden parts of the system?

Building regulations actually stipulate that where mains water hardness exceeds 200ppm (parts per million), feed water to water heaters and the hot water circuit of combination boilers must be chemically treated to reduce the rate of limescale accumulation.

Unless you are a competent and experienced DIYer, we would advise anyone needing to descale a boiler, heat exchanger or other element of the plumbing system to bring in professional help as the chemicals involved are high strength, potentially dangerous and the process isn’t straightforward. Note that if you have a gas-powered system you’ll need a CORGI-registered tradesperson for the job if you’re planning to remove the main heat exchanger for descaling.

Depending on the age of your heating system and the hardness of your water, if you’re having significant issues with limescale build-up in your system it may be too far advanced to be removed and you’d be advised to replace the faulty component.

Keeping on top of limescale and being vigilant about descaling your outlets and system will help to reduce the risk of Legionella as well as reducing your maintenance bills and running costs.