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Hard water in Kent: protecting your boiler and shower
What hard water does to boilers, showers and taps, what the regulations say about it, and what actually helps.
If your kettle furs up and your shower screen never looks clean for long, you already know the answer. Much of Kent has hard water. Ashford is supplied by South East Water and Folkestone by Affinity Water, and both towns are classed as hard water areas. That chalky deposit is limescale, and it does more than mark the glass.
What hard water is
Rain soaks through the ground and picks up minerals, mainly calcium and magnesium, as it passes through rock such as chalk and limestone. The more of those minerals in the water, the harder it is. Hard water is safe to drink. The problem is what happens when it is heated: the minerals come out of the water as limescale and stick to whatever is hot.
Your water supplier can tell you the hardness for your postcode, which is worth knowing before you choose a new boiler or shower.
Where limescale causes problems
Combi boilers
A combi heats water instantly as it passes through a heat exchanger, and that is exactly where scale builds up. Over time it restricts the flow and makes the boiler work harder. Typical signs are hot water that goes hot and cold, water that takes longer to heat up, or a kettling noise from the boiler.
Hot water cylinders
Scale collects on the coil and on the immersion heater element, which makes heating the water slower and less efficient.
Showers and taps
Shower heads clog and spray sideways, thermostatic shower valves can stick, and taps start to drip as scale builds up on the washers and cartridges. Electric showers are particularly prone, because they heat water inside the unit.
Appliances
Kettles, washing machines and dishwashers all suffer in the same way.
What the regulations say
Building Regulations guidance in England on energy efficiency recognises the problem. Where mains water hardness exceeds 200 parts per million, it says provision should be made to treat the feed water to water heaters and the hot water circuit of combination boilers, to reduce the build-up of limescale and the loss of efficiency that comes with it. In practice that usually means fitting a scale reducer when a new combi goes in. Many boiler manufacturers also set out water quality requirements in their installation instructions.
Ways to reduce limescale
Scale reducers
A scale reducer is a small unit fitted on the cold water supply to the boiler. There are different types, including electrolytic and magnetic, and they are a common choice on combi installations in hard water areas. They are fitted on the water feed and do not soften the water for the whole house.
Water softeners
A softener treats the water for the whole house using salt and ion exchange. It is a bigger investment and needs regular salt top ups. It is usual to keep one tap, often the kitchen cold tap, on unsoftened water for drinking.
Regular cleaning
Soaking shower heads and tap aerators in a descaler keeps the flow up. Wipe shower screens after use to stop deposits building up.
Look after the heating system
Limescale affects the hot water side. The heating side is a sealed loop and should be protected with inhibitor, and that is checked at a boiler service.
If you already have a combi
If your combi is a few years old and the hot water has become slower to arrive or less steady once it does, mention it at the next service. Scale on the hot water side can sometimes be cleared, and sometimes the affected part needs replacing. Either way, it is better found in autumn than as a breakdown in the middle of winter. If there is no scale reducer on the cold feed, ask whether fitting one makes sense.
Thinking about a new boiler or bathroom?
Hard water is worth factoring in. A combi with a scale reducer is a perfectly good choice in Kent, but if you are deciding between boiler types, combi or system boiler sets out the other questions that matter. In a new bathroom, a shower valve and shower head that are easy to descale and get parts for will save hassle later.
Help with hard water in Ashford, Folkestone and Hythe
I fit scale reducers on new boiler installations, replace scaled-up taps, valves and shower parts, and fit new bathrooms across Ashford, Folkestone, Hythe and the surrounding area. See boiler installation, bathroom renovation or general plumbing, or call for a free quote.
Common questions
Is the water hard in Ashford?
Yes. Ashford is supplied by South East Water and is classed as a hard water area. Your supplier can confirm the hardness for your postcode.
Does a combi boiler need a scale reducer?
In hard water areas, usually yes. Building Regulations guidance says that where mains water hardness exceeds 200ppm, the hot water circuit of a combi should be treated to reduce limescale.
Is hard water bad for my boiler?
It mainly affects the hot water side. Limescale builds up in a combi's heat exchanger and in cylinders, reducing flow and efficiency over time.