The terms you'll hear
- Hard water
- Water carrying dissolved calcium and magnesium picked up from limestone and chalk ground. Measured in parts per million (ppm) or degrees Clarke. Above roughly 200 ppm you'll see scale quickly.
- Ion exchange
- The process inside a softener: hardness minerals in the water swap places with harmless sodium ions held on resin beads. The water leaving the unit is genuinely soft, not just conditioned.
- Resin bed
- Thousands of tiny plastic beads in the pressure tank that hold the sodium and grab the hardness. Resin lasts roughly 10–15 years before it loses capacity.
- Regeneration
- When the resin fills with hardness, the softener flushes it with strong brine from the salt tank, washing the calcium to drain and recharging the beads. Metered units do this based on litres used; timer units do it on a clock whether needed or not.
- Brine tank
- The salt reservoir. Tablet or block salt dissolves here to make the brine used in regeneration.
- Bypass valve
- A valve that routes water around the softener so it can be serviced without turning off water to the house.
- Reverse osmosis (RO)
- A separate drinking-water system that pushes water through a very fine membrane to strip out dissolved solids, giving bottled-quality water at a dedicated tap.
- Pre-filter
- A sediment or carbon cartridge fitted upstream to catch grit, rust and chlorine before they reach the resin or an RO membrane.
How a softener works, step by step
- 1
Mains water enters the softener's pressure tank, which is filled with ion-exchange resin beads coated in sodium.
- 2
As the water passes through the bed, calcium and magnesium stick to the beads and sodium is released in their place. Soft water leaves the unit and feeds the house.
- 3
A hard-water tap is usually kept for drinking and cooking, teed off before the softener.
- 4
The control valve counts the litres treated. When the resin approaches capacity, it starts a regeneration.
- 5
Brine is drawn from the salt tank and flushed slowly through the resin, stripping off the hardness and sending it to drain.
- 6
The bed is rinsed, the tank refills with water to make the next batch of brine, and normal service resumes — usually overnight, in about 20–40 minutes.
The problems it solves
Limescale in kettles, showers and pipework
Scale coats heating elements and narrows pipework. A softener stops new scale forming and, over months, existing deposits gradually break down.
Boilers and immersions eating electricity
Even a few millimetres of scale on an element forces it to work far harder. Removing hardness protects efficiency and extends appliance life.
Appliances failing early
Washing machines, dishwashers and combi boilers are the usual casualties of hard water. Soft water is one of the cheapest forms of insurance for them.
Soap that won't lather; scum in the bath
Hardness reacts with soap to form scum. Soft water lathers with a fraction of the detergent and rinses cleanly.
Dry skin, dull hair, stiff towels
Soap residue left on skin and fabric by hard water is a common irritant. Many households notice the difference in the first week.
Spotting on glassware and taps
White marks after washing are dried hardness minerals. They disappear with softened water.
Why filters and systems need servicing
Water treatment equipment is consumable by design. Cartridges, membranes, resin and seals all have a working life, and a system left alone quietly stops doing its job long before it fails outright. These are the faults we see most often.
Blocked sediment and carbon filters
Cartridges load up with grit, rust and sand. The first symptom is falling pressure at the tap, then a metallic or chlorinated taste as carbon exhausts. Typical life is 6–12 months.
Fouled or scaled RO membranes
Membranes clog with minerals and biofilm, so output slows to a trickle and the waste ratio climbs. Most need replacing every 2–3 years — sooner if the pre-filters were left too long.
Salt bridging in the brine tank
A hard crust of salt forms above an empty space, so the unit draws no brine and can't regenerate. Water goes hard again while the tank still looks full.
Iron-fouled or channelled resin
Iron and manganese coat the beads, and worn resin lets water carve channels straight through the bed. Both mean partial softening. A resin clean can recover it; badly degraded beds need replacing.
Sticking valves and worn seals
The control valve's seals and pistons wear. Symptoms are constant running to drain, water in the salt tank, or regenerations that never finish.
Programming drifting out
After a power cut or a change in household size, hardness settings and regeneration times are often wrong — wasting salt or leaving water partly hard.
An annual service covers all of the above. See what's included in a service visit.