A hidden leak can quietly waste water, lower pressure, and damage walls or floors long before you see an obvious puddle. According to the team at 100% Plumbing (Calpe), the fastest way to avoid expensive repairs is to spot the early clues and get the right diagnosis before the damage spreads.
If you’re in Calpe, Benissa, Moraira or anywhere on the Costa Blanca, here are the most reliable signs to watch for.
1) Your water bill jumps for no clear reason
A sudden increase in consumption is one of the most common “silent leak” clues—especially if your habits haven’t changed (no guests, no garden watering increase, no new appliance).
What to do:
Compare the last 2–3 bills and check if the increase is consistent. If it is, it’s time for a proper check through a Domestic Water Supply assessment.
2) Your water meter moves when everything is off
This is the clearest DIY check for a hidden leak.
Quick test:
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Turn off all taps and make sure no appliances are running
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Note the meter reading
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Wait 30–120 minutes (no water use)
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If the meter changes, you likely have a leak
This meter-check method is also widely recommended by water utilities, for example: Thames Water – Identifying leaks.
3) Damp patches, bubbling paint, or peeling plaster
Hidden leaks often show up as staining, paint bubbling, soft plaster, or swollen skirting boards—especially near bathrooms, kitchens, or behind washing machines.
Tip: Damp that keeps returning after ventilation/cleaning is a strong hint it’s not just humidity.
If you’re also fighting persistent moisture, you may find it helpful to read Damp Proof Your Home alongside the plumbing checks.
4) Musty smells or visible mould in “random” spots
Mould behind furniture, inside cupboards, or around skirting can be a sign of moisture trapped in walls or floors from a slow leak.
What to do:
Don’t just treat the mould—find the moisture source. A General Plumbing inspection can help locate the cause safely.
5) Sudden drop in water pressure (whole home or specific areas)
Leaks can reduce pressure—especially if the leak is on the main feed or a key branch.
Rule of thumb:
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One tap affected → likely local (fixture/valve)
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Whole house affected → possible supply issue, PRV issue, or leak
If pressure dropped suddenly and you can’t explain it, book help via Plumbing Services.
6) You hear water when nothing is running
Listen for:
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faint hissing near toilets
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dripping sounds behind walls
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“whooshing” in pipe runs
Toilets are especially sneaky because a leak can run silently into the bowl.
7) Warm spots on floors or unexplained damp in outdoor areas
In some homes, hidden leaks can appear as:
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a warm patch on a floor (if hot water is leaking)
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damp soil/wet patches outside even in dry weather
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unusually green grass in one area
These are strong “call a pro” signs, because leak location matters (and digging blindly gets expensive fast).
When a hidden leak is urgent
Call a professional immediately if you notice:
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water meter movement + damp/staining
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sudden major pressure drop
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ceiling bulging, dripping, or electrical risk
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active flooding
If you’re unsure, go straight to Contact Us—especially if you need fast help on the Costa Blanca.
What 100% Plumbing can do (and how we keep it efficient)
At 100% Plumbing, we focus on pinpointing the cause with practical, step-by-step diagnosis—so you don’t pay for unnecessary work. Based in Calpe, we cover the Costa Blanca and provide 24/7 emergency support when needed.
Book an inspection through Contact Us.
FAQs: Hidden Leaks in Costa Blanca Homes
What is the easiest way to check for a hidden water leak?
The easiest method is a water meter test: turn off all water use, note the meter reading, wait 30–120 minutes, then check if it changed. If it moved, you likely have a leak.
Can a hidden leak cause low water pressure?
Yes. A leak—especially on a main feed or major branch—can reduce pressure because water is escaping before it reaches taps and appliances.
What are the most common signs of a hidden leak?
A higher bill, a moving water meter when everything is off, damp patches, mould/musty smells, unexplained puddles, and sudden pressure drops are among the most common clues.
Is a hidden leak always visible?
No. Many leaks stay behind walls, under floors, or underground. The leak itself may not be visible, but its effects (damp, stains, meter movement, odour) usually are.
When should I call a professional plumber for a hidden leak?
Call a professional if the meter test suggests a leak, if you see recurring damp or staining, if pressure drops suddenly, or if you suspect a hot-water leak (warm floor spots). In Calpe and the Costa Blanca, you can book help via Contact Us.
