Water Leaks at Home – What London Homeowners Need to Know

Water leaks in the home are not always obvious, but early detection is essential to avoid costly damage, high water bills, and disruption to your household. At Greater London Water, we encourage homeowners across London to monitor their water usage, keep an eye on pressure levels, and recognise the signs of hidden leaks.

By staying proactive with checks, maintenance, and technology-assisted detection methods, you can protect your home, preserve your plumbing system, and save money over time.


How to Spot a Water Leak at Home

Not all leaks are visible. Here are some easy, practical ways to monitor for hidden leaks inside your home:

Check Your Water Bill

Review your water bills regularly. If your usage is increasing unexpectedly and can’t be explained by things like guests or garden watering, you might have a leak. If you're unsure, many suppliers offer online usage monitoring to help track your consumption.

Test Your Water Pressure

A drop in water pressure at your taps or shower can signal a leak. Try shutting off all taps, then open one again. If the pressure surges and then drops, that could indicate water loss elsewhere in the system.

 

Watch Your Boiler or Water Heater

Frequent activation of your boiler or water heater — especially outside of normal use — can suggest a leak in the hot water supply. These are often harder to detect and may require professional investigation.
 

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Where to Check for Common Household Leaks
 

Leaks can happen in several areas of the home. We recommend inspecting these locations frequently:

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Water Tank or Boiler

Look for pooling water, rust stains, or hissing sounds around your water tank or boiler valves. If you notice signs of leakage, it's wise to involve a specialist immediately.

 

Toilets

Add a few drops of food colouring to your toilet cistern. If the colour appears in the bowl without flushing, there’s a leak between the cistern and the bowl.

 

Showerheads

Irregular flow or reduced pressure from your shower could indicate a leak. Unscrew and inspect your showerhead for wear and tear.

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Washing Machines and Dishwashers

These appliances often shift during use. Regularly check the hoses and connectors at the back to ensure they're secure and leak-free.

Outdoor Taps and Irrigation

Don't forget to inspect garden taps and irrigation systems. Leaks in these areas can go unnoticed but still drive up your water bills.

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Common Signs of a Water Leak Inside Your Home

If you're concerned about potential leaks in your home, staying vigilant for certain signs can help you catch issues early, potentially saving on costly repairs and water waste. At Greater London Water, we advise homeowners across London to watch for the following common indicators of water leaks:
 

Unexpected Increase in Water Usage or Bill

A sudden spike in your water bill or meter reading that can’t be explained by your usual water habits is often the first sign of a hidden leak somewhere in the system.

 

Damp Spots on Walls, Floors, or Ceilings

Unexplained damp patches on surfaces can indicate that water is leaking from pipes hidden behind walls, under floors, or above ceilings.

 

Mould or Mildew Growth

If you notice mould or mildew forming in parts of your home that aren’t typically moist, this could be a result of hidden moisture caused by a leak.

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Water Stains or Discolouration

Stains or yellowing on ceilings, floors, or walls are usually a sign that water has been leaking over time and has started to affect building materials.

 

Reduced Water Pressure

A drop in water pressure when using taps, showers, or appliances can mean that water is escaping through a leak before reaching its intended destination.

 

Constant Sound of Running Water

If you hear water running when no taps or appliances are in use, there may be a hidden leak within your home’s plumbing or underground water supply pipe.

 

Musty or Unpleasant Odours

Persistent musty smells in areas like basements, cupboards, or utility spaces could be due to dampness caused by a slow, unnoticed leak.

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Puddles or Pooling Water

Visible water collecting in places where it shouldn't be — such as near appliances, along skirting boards, or outside the property — should be investigated promptly.

 

Cracks in Walls or Foundations

Long-term water damage can weaken structures, sometimes leading to cracking in walls or the home’s foundation due to shifting or settling.

 

High Humidity Levels

If the air inside your home feels damp or humid without any heating or weather-related cause, excess moisture from a leak may be to blame.


How to Check for Water Leaks at Home with Your Water Meter (DIY Method)

Identifying a leak can often be done at home using your water meter. At Greater London Water, we recommend the following DIY steps to help you determine whether water is leaking inside or outside your property:
 

Stop All Water Usage

Ensure no water is being used in the home. This includes turning off taps, showers, toilets, dishwashers, washing machines, and outdoor hoses.

 

Find Your Water Meter

Most residential water meters in London are located outside the property, near the pavement or in a ground-level box close to the boundary.

 

Record the Current Meter Reading

Write down the exact meter reading before beginning the test. Be sure to include both the main numbers and any decimals or dial positions.

 

​Wait

Avoid using any water for a few hours, or ideally overnight, to get the most accurate result from the test.

 

Check the Meter Again

After the waiting period, return to the meter and note the new reading. If the numbers have changed despite no water usage, it likely indicates a leak somewhere in the system.

 

Isolate the House Supply

To confirm whether the leak is inside or outside your home, turn off your internal stop valve (usually located under the kitchen sink). Then recheck the meter. If it’s still moving, the leak is likely on your underground water supply pipe.

 

Seek Professional Help

If the test confirms a leak on your water supply pipe, Greater London Water is ready to help. Our engineers use advanced technology to locate underground leaks quickly and carry out trenchless replacements where needed.

Need Help with Water Leak Detection and Repairs? Contact Greater London Water

Greater London Water is trusted across London for accurate water leak detection and professional water supply pipe replacement. Our experienced engineers use industry-leading methods to find hidden leaks and deliver reliable solutions with minimal disruption.

If you suspect a leak in your home or on your underground water supply pipe, we can help. Our team is equipped to handle all types of leak detection and provide a long-term fix that meets UK Water Regulations.

To get a free quote, contact Greater London Water on 0207 1234 996 or email hello@greaterlondonwater.co.uk. Our team will be happy to arrange a consultation and help restore the safety and efficiency of your water system.

For more useful help and advice see our other articles here.