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We recommend you contact us before purchasing one of our hard water filters. This is so we can help you choose the most appropriate filter based on how hard your water is. You may prefer a hard water filter for your whole house, or just the kitchen sink, for example. For a whole house system you need a mains hard water filter.
If you live in an area of the UK with hard to very hard water you may wish to consider one of our OneFlow Hard water filters.
Call 01352 838 281
It's water that is high in certain minerals. The minerals that contribute to water hardness are calcium and magnesium, mainly in combination with bicarbonate, sulphate and chloride. When hard water is heated above 61 degrees (or as it evaporates) the balance between the dissolved minerals is upset and the bicarbonate converts to carbonate. This is what causes limescale!
Hard drinking water is not considered to be harmful to health, in fact, those minerals, like calcium and magnesium, are important for good health. It's the scale it causes that's an inconvenience, but it can be resolved by buying and installing either a hard water filter for your drinking water; the Pearl H, or a whole house system such as the Doby Whole House Hard Water Filter, or Doby Taste and OneFlow Hard Water Filter.
Yes, hard water can cost you money, both in terms of heating costs and having to replace white goods. It can shorten the life of clothing, household appliances such as washing machines and dishwashers, and plumbing such as hoses and pipes; basically anything that hard water comes into contact with, especially where there's a heater involved. Boilers, kettles, coffee machines, washing machines, dishwashers, and immersion heaters are particularly susceptible to lilmesacle fouling. You will also get limescale clogging up the pipes and radiators of your central heating making them less efficient - you'll need to turn the radiators up to get the same temperatures, using even more costly energy!
Look at the map to see whether you're likely to have hard water. Water Hardness is measured as the equivalent amount of calcium carbonate in parts per million (mg/l).
| Hardness as CaCO3 mg/l | Water Hardness Levels |
| 0-50 | Soft |
| 51-100 | Moderately Soft |
| 101-150 | Slightly Hard |
| 151-200 | Moderately Hard |
| 201-300 | Hard |
| 300- | Very Hard |
The table below lists UK counties with the hardest water.
| County | Water Hardness Level |
| Bedfordshire | Hard to Very Hard |
| Berkshire | Hard to Very Hard |
| Buckinghamshire | Hard to Very Hard |
| Cambridgeshire | Hard to Very Hard |
| Dorset | Hard to Very Hard |
| Essex | Hard to Very Hard |
| Gloucestershire | Hard to Very Hard |
| Greater London | Moderately Hard |
| Hampshire | Hard to Very Hard |
| Hertfordshire | Hard to Very Hard |
| Kent | Hard to Very Hard |
| Oxfordshire | Hard to Very Hard |
| Surrey | Hard to Very Hard |
| Sussex | Hard to Very Hard |
| Wiltshire | Hard to Very Hard |
If you live in Scotland; you're unlikely to have hard water, although does seem to be changing due to increased use of borehole water in the public supply. However, many properties in Scotland that have private water supplies that draw water from wells and boreholes. Because that water flows through underground water courses and trickles through rock it can pick up all sorts of minerals. Those dissolved minerals are just the same as what is found in hard water from municipal supplies, and in some cases even worse.
A water filter works by forcing the fluid through a medium that has tiny pores. Anything larger than those pores gets stuck while the liquid flows through. Minerals that cause hard water, calcium carbonate and magnesium carbonate (CaCO3 and MgCO3 respectively), are dissolved in the water. That means they don't really have physical dimensions big enough for standard filtration to work.
"Aha, so no filter will work for limescale then", you might say. In the strictest sense that's correct, however; we have filter cartridges that treat and condition those pesky limescale causing minerals by altering their ionisation properties. This converts them into soft, microscopic crystals that just flow right through your appliances and plumbing without sticking and causing scale.
Those water filter cartrdges fit inside all of our standard water filter housings and so we feel it's fair enough to describe one of these hard water treatment systems as a hard water filter.
If you're having trouble with limescale building up on your shower head then it is possible to buy small, dedicated units that can treat the hard water. These may work, but it depends very much on the concentration of calcium carbonate and magnesium carbonate in your locality. The drawback with these is often that have to replace them frequently - including the whole shower head in many designs. And it's not always clear what the quality is if you are buying them cheap. Additionally, shower filters for hard water only treat the one item, so you don't get any benefit in other parts of the home.
This is something that often confuses people, a water softener is a specific type of installation that treats hard water. It's not a filter, and other methods of treating hard water are not water softeners and do not soften the water.
What a water softener system does is replaces the hard ions, that is, the calcium carbonate and magnesium carbonate (CaCO3 and MgCO3 respectively) with sodium ions.
The water that comes out of a water softener is soft water. However, these water softeners add sodium to the water, and many people aren't keen on drinking it for that reason.
Modern water softener systems are more efficient than older models. So it's likely that if you drink and consume the average amount of water then your sodium intake will only increase by about 5%.
Of course, some would argue, if you're in a high risk group for heart health problems then even that small amount is too much and should be avoided.
Maintenance on water softener systems is fairly high. You need to replenish the sat supply regularly, 2 to 3 times a week depending on the type and flowrate of the system.
This can work out to be both onerous and costly.
If you want to see some have a look at the category by clicking water softener systems.
When choosing a whole house water filter, also known as a mains water filter, you need to ensure that it is the right size.
While whole house water filters do reduce the pressure of the water in your house it's more likely that it's the flow rate that you need to be concerned with.
Water pressure and flow rate are related, but they are not the same. You can have a high flow rate but low pressure, and high pressure but low flow rate too.
A good example is when you put your thumb over a hose pipe to increase the pressure of the water coming out. The result is that the volume of water coming out is much lower - the flow rate has reduced.
Imagine that you install a water filter that is too small for your house, it will create back pressure, but also restrict the flow rate after the filter. That will mean that running a bath, taking a shower, or even just filling the kettle might be frustratingly slow.
You could buy a filter housing with bigger ports that allows water to travel through the filter more quickly. But that's not a good solution because for the filter to work correctly and efficiently the water must have sufficient time in contact with the filter medium.
Speeding it up means it doesn't remove what you want to take out of the water, so you might as well not bother having a water filter at all.
The solution to this is to have a whole house water filter of a size and specification that is correct for your house and requirements.
The size varies depending on water you want to filter out. If it's just sediment then the filter cartridges allow a higher flow rate so you can install a smaller filter housing.
But if you want to remove chemicals using a whole house water filter then you'll need a bigger unit that allows a greater volume of water through. The bigger the unit, the greater the volume that can be treated in any given timescale
Water demand varies in any house and once you've established what it is you want to improve about your water you need to think about that demand.
Ideally, consider the size of the house, usual occupancy, but also peak occupancy. Let's assume there are two people living in a 4 bedroom property, usual water demand may peak at 4 litres per minute. That can be divided into one person taking a shower while another has started a washing machine cycle, and then goes and flushes the loo. Guess what the person in the shower is thinking as they lose water flow because the filter is too small?
Even with a filter system big enough for two in that house, what happens when you have a visitors? Potentially, that could be six extra people, so you need to plan for that greater demand on your water usage.
Ideally, give us a call and we'll be able to help you find the correct filter, and the right size for your property: 01352 838281
As mentioned in the Hard Water Filter section above you can't really filter out limescale because it's caused by dissolved minerals coming out of solution and coating surfaces. But you can treat the water at point of entry to your property or just for certain taps or appliances.
Many of the options available are fitted into filter housings so they are easy to anstall and maintain.
One of the most difficult questions asked about
We're here to help. Call us on 01352 838 281 if you have any questions about hard water filters.
Read our blog post about hard water HERE
What our customers have to say about us
18 Oct 2023Great 3-way tap, which was well packaged, with clear instructions. Our plumber commended the tap as good quality and easy to plumb in and connect to both water supply and under-sink filter. Looks brilliant in our new kitchen. Thanks to Fountain Filters for a helpful website and speedy delivery service.
12 July 2023Great product, simple to install including hints on common installation challenges which I did have and overcame instantly because of the care taken by the seller. Whole of house now has soft water without a noticeable drop in pressure. Has made a massive difference throughout.
1 Dec 2023It was a small but important order: replacement o-ring with silicon for my water filter housing. when I told them I had not received the articles after 7 days, they without fuss dispatched a replacement with the result I received the original and replacement 3 days later! Very responsive customer service.
17 June 2023After moving into a property with a fresh water supply, I turned to Fountain Filters for advice on replacing the water filter system. I purchased the Moby Twin Sediment System and it has been a worry-free system. Even changing the filters was far easier than the old system. Cannot fault this company on speed of service or quality of advice.
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Fountain Filters, Strowger House,
Sandy Lane Ind. Est.
Newcastle upon Tyne, NE3 5HE, UK.
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