Hidden water leaks and high bills: How to spot the warning signs early

Everything else in this article is a sign. This is the only thing that gives you a yes or a no, and it takes two hours of doing nothing.

1. Turn everything offClose all taps and showers. Stop the washing machine, the dishwasher and any irrigation.
2. Check the toiletsMake sure no cistern is quietly refilling in the background. That alone will fail the test.
3. Read the meterWrite down the full reading, including the small red dials — that is where a slow leak shows up first.
4. Wait two hoursWithout using any water at all. Not one tap.
5. Read it againIf the number moved, water is leaving the system somewhere you cannot see.

Water may be escaping continuously even when no taps or appliances are in use. The usual sources are running toilets, leaking pipe joints, slab leaks, underground supply leaks, faulty water heaters, irrigation leaks and appliance hose leaks.

The US Environmental Protection Agency’s WaterSense programme reports that the average household wastes nearly 10,000 gallons of water a year — around 38,000 litres — through leaks that are never found.

Not every leak makes a puddle:

• pipes are concealed behind walls or under floors;
• small leaks evaporate before they pool;
• toilets leak silently into the bowl;
• outdoor irrigation leaks soak straight into the soil;
• water heater leaks start slowly;
• holiday homes sit empty for months at a time;
• hard water and limescale attack valves, joints and appliances.

In Calpe and across the Costa Blanca the last two matter most. Long vacancy periods mean nobody is there to notice, and hard water means there is always something being worn away — see how hard water affects pipes, boilers and appliances in Costa Blanca homes.

Read next
Plumbing maintenance checklist for holiday homes in Calpe and the Costa Blanca

A hidden leak shows several small signs before it becomes obvious. This separates a normal change in household habits from something that needs attention.

1. Your water bill has increased without a clear reason

A sudden or steady increase is one of the strongest early indicators. Bills rise for seasonal use, guests, irrigation or pool filling — but if none of those apply, consider a leak.

For wider supply concerns, our domestic water supply service can identify whether the issue is inside the home, near the supply line or at a fixture.

2. The water meter moves when everything is off

Covered in full at the top of this article — it is the one test that gives a definite answer rather than an indication.

3. You hear water running when no taps are open

Running, dripping, hissing or rushing sounds can indicate a concealed leak, especially if they continue with every fixture closed.

4. Damp patches, stains or musty smells appear

Hidden leaks show as moisture before they show as dripping. Damp walls, warped flooring, ceiling stains, peeling paint, swollen skirting boards and musty smells all point the same way.

5. Water pressure has dropped

Low pressure has several possible causes, and a hidden leak is one of them. If water escapes before it reaches your taps, pressure falls across the property.

Hard water also reduces flow over time by building limescale inside pipes and fittings. Our water treatment service covers softening and filtration for Costa Blanca properties.

6. A toilet keeps refilling or running

A running toilet is one of the most common causes of water waste, and it rarely looks like a leak because the water runs silently from the cistern into the bowl.

7. The water heater or boiler area is damp

Leaks near water heaters start small. A valve, a pipe connection, a pressure relief valve or the tank itself may drip slowly for weeks before a larger failure.

8. Outdoor areas are wet when they should be dry

Outdoor leaks hide well, because water soaks into soil, garden areas, terraces or irrigation zones instead of pooling.

Related reading: who can fix a leaking outdoor tap in Calpe, et how to detect a slab leak before it damages your property.

Gathering a few facts before calling speeds up the diagnosis considerably. Note down:

• when the bill first increased;
• whether the meter moves with all water off;
• whether damp patches are growing;
• whether pressure changed suddenly;
• whether it affects hot water, cold water or both;
• whether any toilet keeps running;
• whether irrigation or outdoor taps may be involved;
• whether the water heater area is dry;
• how long the property was left empty.

If a leak is active and water is spreading, find and close the main shut-off valve. Our guide to what a stopcock is and why every homeowner should know where it is explains how it isolates the water in an emergency.

Act quickly too if the property is a holiday home or rental that may be left empty again soon — that is the situation where a slow leak does the most damage for the longest time. If you are unsure whether it is urgent, read Quand faire appel à un plombier professionnel. If a pipe has already failed outright, who can repair a burst pipe in Calpe is the one you want.

We help homeowners, landlords, property managers and holiday-home owners across the Marina Alta investigate hidden leaks, unexplained high water bills, low pressure, damp patches, slab leaks, running toilets and hot water system leaks.

Our team inspects visible pipework, tests the common leak points, assesses water pressure, checks shut-off valves and recommends practical next steps. If the problem traces back to ageing pipework, we can also advise whether a targeted repair or a replacement is the better long-term option — our guide on whether to repair or replace old plumbing pipes covers the warning signs.