Water Hardness in My Area - How Hard is My Water? - Filter Flair

"How hard is my water", is something we're asked a lot here at Filter Flair.

If you're like us, you want to know exactly what’s in your water so you can decide on the best water filtration system for your water type/

Sometimes it’s fairly straightforward to know whether you need a hard water filter. Tell-tale signs such as limescale build up taps and water stains on your glasses are a sure sign that you live in a hard water area, but until you know exactly what’s in your water you can't make an informed decision.

That’s why we’ve put together a simple guide that will not only tell you how hard the water is in your area, but also what else might be in it!


First of all, let us explain the differences of hard vs. soft water. 


Water hardness is the measure of calcium and magnesium that’s present in water. When rainwater falls from the sky it is naturally soft, however as it makes its way through layers of soil and rock before joining a water source such as a river, reservoir or natural lake deep in the ground, it accumulates minerals such as calcium and magnesium. Because water suppliers use water from a variety of sources, water hardness varies widely throughout the UK. 

Of course, nobody wants limescale to build up on their tap, and that’s why we’ve created this guide to help you understand what filter is best for you! 


Step One: Find your supplier

The first step is to find out who your local water authority is. You may already know this, and if so, skip to step 2. If not, then don’t worry; to find out it’s really easy.

Water UK has a useful tool for finding your water supplier by postcode. Go to the following link and find out who your supplier is by typing in your postcode.



Step Two: Find out your water hardness by postcode

Now that you know who your supplier is, we can find out exactly what your water hardness is based on your postcode. Find your water supplier and click the link to take you to the relevant page. Here you will need to enter your postcode, which will then give you the details about your water quality: 

Anglian Water

Dŵr Cymru Cyf

Northern Ireland Water

Northumbrian Water

Scottish Water

Southern Water

Southwest Water

Severn Trent Water

Thames Water

United Utilities

Wessex Water

Yorkshire Water

(Don’t see your supplier? Type into Google “water hardness *Your Supplier*” and it should take you to the right page.)


Step 3: Review your water

Now that you have your report, you can see how hard the water is and, ultimately, what filter you should use. Compare the Clark Degrees in the report to the chart.

Below 50mg Ca/l

If your water falls below 50mg Ca/l you have soft water and shouldn’t need to worry about limescale build up. The Filter Flair Carbon Block Filter for Soft Water will be the ideal option to replace external/undersink filters.


Between 50-100mg Ca/l

Over 50mg Ca/l is where you may want to think about a filter with scale inhibitor to reduce limescale build up. It really comes down to judgment as water at, for example 51mg Ca/l may not cause too many issues with scale however over 70mg Ca/l and it’s likely you will have seen limescale build up around your taps. The Filter Flair Carbon Filter for Hard Water is ideal for your undersink filter systems or external inline fridge filters. 


Above 100mg Ca/l

If your water hardness is above 100mg Ca/l then it’s likely you are well aware of having hard water and you have probably tackled limescale around your home. The Filter Flair Carbon Filter for Hard Water will certainly help stop limescale building up, but of course will be limited to the outlet the filter is connected.


If the hard water is resulting in an undesirable, metallic taste you may want to look at a limescale removal filter. These types of filters work differently from a scale inhibitor filter by utilising ion exchange technology to remove limescale from the water.


Still not sure? Contact us and let us help find you the right filtration solution.