How Exeter's Hard Water Affects Your Plumbing

Exeter has hard water. Not brutally hard like London, but hard enough to fur up kettles, clog showers, and slowly damage boilers. Here's what it means and what to do.

Understanding Hard Water

What Makes Water Hard?

Hard water contains dissolved calcium and magnesium from the rock it passes through. In Devon, water comes mainly from Dartmoor and local aquifers, passing through limestone and other mineral-rich geology.

Exeter's Water Hardness

South West Water supplies Exeter. Typical readings:

Area	Hardness (ppm)	Classification
Exeter city	120-180	Moderately hard
Topsham	130-170	Moderately hard
Exwick	150-200	Moderately hard to hard
Pinhoe	140-180	Moderately hard

For comparison:

• Soft water: Under 60 ppm
• Hard water: Over 180 ppm
• Very hard: Over 300 ppm (London can hit 350+)

We're in the middle, but still hard enough to cause problems over time.

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How It Affects Your Home

Kettles and Appliances

What you'll see: White/grey scale buildup on heating elements.

Impact:

• Reduces efficiency (element has to heat through scale)
• Increases energy costs
• Shortens appliance life
• Kettles make horrible noise

Worst affected:

• Kettles
• Coffee machines
• Steam irons
• Dishwashers

Showers and Taps

What you'll see: Crusty deposits on showerheads, reduced flow, stiff mixer cartridges.

Impact:

• Blocked showerhead holes
• Reduced water pressure
• Mixer taps become hard to turn
• Thermostatic valves fail

Boilers and Heating

What you'll see: You won't, until it breaks.

What's happening:

• Scale builds up in heat exchangers
• Reduces efficiency
• Causes localised overheating
• Eventually blocks flow or causes failure

The scary bit: Boiler heat exchanger replacement costs £300-600. A new boiler is £2,000-3,500.

Pipes

Over decades, hard water deposits narrow pipes internally. In very old properties, this can reduce flow significantly.

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Quick Fixes

Descaling Showerheads

Easy method:

1. Unscrew showerhead
2. Soak in white vinegar (neat) for 2-4 hours
3. Scrub holes with old toothbrush
4. Rinse and refit

Or: Use a dedicated limescale remover from Wilko or B&Q.

Cleaning Taps

Method:

1. Soak a cloth in vinegar
2. Wrap around tap spout
3. Leave 30-60 minutes
4. Scrub and rinse

For stubborn scale: Limescale remover gel, applied directly.

Kettles

Method:

1. Fill halfway with water
2. Add 2-3 tablespoons of white vinegar or citric acid
3. Boil
4. Leave 30 minutes
5. Empty, rinse, boil fresh water, discard

Do this monthly to prevent buildup.

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Longer-Term Solutions

Water Softeners

How they work: Ion exchange removes calcium and magnesium, replacing with sodium.

Pros:

• Eliminates limescale completely
• Appliances last longer
• Nicer feel to water
• Less soap needed

Cons:

• Installation cost (£1,500-2,500 fitted)
• Running costs (salt, servicing)
• Need space for unit
• Softened water not ideal for drinking (sodium content)
• Separate drinking water tap recommended

Worth it? If you're in Exeter long-term and own your home, probably yes. Payback through appliance life and energy savings is typically 5-8 years.

Scale Inhibitors

Electronic/magnetic: Clip-on devices that claim to alter calcium's behaviour. Evidence is mixed. Some people swear by them, scientific support is limited.

Cost: £50-200

Worth it? Cheap enough to try. Not a substitute for softener in hard water areas.

Electrolytic: Inline devices that use small electrical charge. Better evidence than magnetic ones. Often fitted to boilers.

Cost: £100-300 fitted

Phosphate Dosing

How it works: Adds tiny amounts of food-grade phosphate that prevents scale formation.

Common in: Commercial settings, some domestic systems.

Pros: Effective, low maintenance Cons: Needs refilling, adds something to water

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Protecting Your Boiler

Regular Servicing

Annual boiler service should include:

• Checking for scale buildup
• Cleaning heat exchanger
• Checking pressure and flow

Inhibitors

Scale reducers can be fitted to the cold feed to your boiler. They dose the water to prevent scale forming in the heat exchanger.

System Flush

If your system hasn't been maintained:

• A power flush removes existing deposits
• Chemical flush is gentler alternative
• Add inhibitor afterward to protect

Cost: Power flush typically £400-600.

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Room by Room Checklist

Bathroom

• ☐ Descale showerhead monthly
• ☐ Clean tap aerators regularly
• ☐ Use limescale remover on tiles
• ☐ Consider squeegee after showers
• ☐ Service thermostatic valves annually

Kitchen

• ☐ Descale kettle monthly
• ☐ Run dishwasher cleaner cycle
• ☐ Clean tap spray heads
• ☐ Check washing machine drain filter

Utility/Heating

• ☐ Annual boiler service
• ☐ Check for scale inhibitor fitted
• ☐ Bleed radiators (air, but also sludge check)

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Signs of Limescale Problems

Act on these:

• Hot water taking longer to come through
• Reduced water pressure (but check stopcock first)
• Boiler kettling (rumbling, banging noises)
• White residue appearing faster than usual
• Mixer taps stiffening

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When to Call a Plumber

DIY handles:

• Descaling showerheads and taps
• Cleaning appliances
• General preventive maintenance

Get help for:

• Fitting water softeners
• Boiler servicing and flushing
• Thermostatic valve replacement
• Pipe flow investigations

I can help with general maintenance and minor plumbing, but for softener installation or boiler work, I'll recommend specialists.

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Hard water hassles? I can descale, clean, and maintain fixtures across Exeter. For bigger plumbing work, I'll point you to the right people. Call 01392 964094 or get a quote.