Everything you need to know about hard water, limescale, and the simple ways to keep your AquaTru working at its best.
If your AquaTru seems to be filtering more slowly than it used to, there are usually two possible reasons. The first is that the unit simply needs routine maintenance, such as a filter change or a descale. The second, particularly in hard water areas, is the natural mineral content of your water supply, which leaves limescale behind as it builds up over time.
Both are common situations for many households across the UK, and in most cases slow filtration can be resolved with routine care, and should not be viewed as an automatic manufacturing fault. This blog will help you identify the likely cause and how to resolve it.
What Is Hard Water?
Hard water is water that contains a high level of dissolved minerals, mainly calcium and magnesium. Rainwater starts out naturally soft. As it soaks down through the ground, it passes through soft rock such as limestone and chalk, both of which are rich in calcium and magnesium, and dissolves small amounts of these minerals as it goes. The more it absorbs, the harder the water becomes by the time it reaches your tap.
Whether your water is hard or soft depends largely on the local geology. In the south and east of England, where the ground is mainly chalk and limestone, water tends to be hard or very hard. In parts of Scotland, Wales, and the north and west of England, where the rock is harder and less soluble, the water is naturally much softer. Hard water is very common. More than 60% of UK homes are supplied with it, so for most households it is simply part of everyday life.
Hard water is safe to drink. The UK's Drinking Water Inspectorate does not set a limit for hardness, because it poses no risk to health. Calcium and magnesium are essential minerals, and as McGill University's Office for Science and Society explains, the small amounts found in hard water can even make a useful contribution to your daily intake. Hard water is not a health concern. The issues it causes are practical ones, mainly the limescale it leaves behind.
It is worth checking your local water hardness so you can plan your maintenance accordingly.
How Hard Water Affects Your AquaTru
Inside any water system, hard water gradually leaves behind deposits of the minerals it carries. This is the same white, chalky substance you may have seen inside a kettle, known as limescale, and it forms for exactly the same reason. When water sits or moves through the system, tiny amounts of calcium and magnesium settle on the internal surfaces and slowly accumulate over time.
In a reverse osmosis system like AquaTru, this build up can begin to coat the components that water passes through, including the membrane at the heart of the system. As the deposits grow, they leave less room for water to flow, which is why filtration gradually slows down. In other words, the unit is not failing. Its internal pathways are simply becoming restricted by mineral build up, in the same way limescale narrows a kettle or a pipe. This effect on reverse osmosis filters is well documented.
The good news is that this build up can be prevented, and when caught early, it is also reversible. Once the limescale is removed through descaling, water can flow freely again and normal performance is restored.
Keeping Your AquaTru at Its Best
Keeping your AquaTru in good working condition is straightforward. As explained in your user manual and in the FAQs section of our website, a little routine care goes a long way. The following steps will keep your water flowing freely.
Know your water hardness. AquaTru works best with water hardness up to 171 mg/L, which is around 9.5 °dH. You can still use AquaTru if your water is harder than this, but it helps to know where you stand so you can plan your maintenance accordingly.
Descale regularly. Descaling is the most effective way to prevent limescale build up and maintain filtration speed. The AquaTru Descaling Kit (Classic and Carafe) uses natural, food-grade citric acid, which gently dissolves the calcium and magnesium deposits that collect inside the system. The citric acid reacts with the limescale and breaks it down, so it can be rinsed away, clearing the internal pathways and restoring normal water flow without harming the components. For areas with moderate hardness, descaling every six months is advisable. In hard water areas, monthly descaling is recommended. Our guide on essential care for your AquaTru walks you through the process, with visual step by step walkthroughs in our videos for the Classic and the Carafe.
Consider a water softener in very hard areas. If your water is significantly hard, a water softener fitted to your supply can reduce the mineral load before it ever reaches your AquaTru. A softener works by a process called ion exchange. Hard water passes through a tank of small resin beads that hold sodium, and as it does so, the calcium and magnesium are drawn out of the water and held by the beads, which release a small amount of sodium in their place. The result is softer water that forms far less limescale.
Replace the RO filter as needed. In hard water areas, the reverse osmosis filter works harder and may need replacing a little more often than it would in a soft water area. This is completely normal, and simply part of keeping your unit producing clean, great tasting water. Take advantage of filter bundles, which are more economical than buying individually, and keep an eye out for occasional sales to save even more on replacement costs.
It Is Not the Hardness That Matters Most
If hard water minerals are harmless, why filter at all?
Beyond calcium and magnesium, tap water can contain chlorine, lead, microplastics, pesticides, pharmaceutical residues and other chemicals. These are the contaminants worth removing, and AquaTru is built to do exactly that. Its four-stage reverse osmosis system removes up to 99% of impurities and reduces total dissolved solids by up to 97%, with performance certified by IAPMO to NSF/ANSI standards.
Whatever your water hardness, AquaTru gives you the same clean, filtered water.
Get the Most From AquaTru
Hard water is something many households across the UK live with, and slower filtration is its most common side effect. It is rarely a fault, and it is easily managed with regular descaling, an awareness of your local water hardness, and the occasional filter change.
More importantly, hard water is no reason to go without truly clean water.
Already own one? A little routine care is all it asks. Not yet? There is no better time to make the change.
Browse the AquaTru range and choose pure, great tasting water for your home.
