If you’ve received a letter, phone call or email from your water company saying you might have a leak, it can feel worrying and even a little confusing. Everything inside your home might seem normal — no dripping taps, no burst pipes, no puddles. But water companies often identify leaks before you even notice them yourself.
They monitor how much water is being supplied to your property compared to typical usage, and if there’s an unusual pattern — often a continuous flow when usage should drop — it can flag as a likely leak. This is particularly common with underground supply pipe leaks, which can quietly waste thousands of litres of water a day without showing any surface signs. Thames Water reports that supply pipe leaks are responsible for around a quarter of water lost in their region each year.
Water companies want to alert you early because leaks can cause structural damage, raise your bills, and put unnecessary pressure on the local water network. Their role is to give you the heads-up, but finding and fixing the leak is usually down to you.
How leaks are identified by water companies
Most water suppliers use two main methods to spot potential leaks: meter readings and district monitoring.
If your property is on a water meter, readings can highlight unexpected, continuous usage. For example, if your household is away for the weekend but the meter shows steady flow every hour, it suggests water is escaping somewhere. Some modern meters even send alerts automatically when they detect continuous flow. According to Ofwat, smart meters have helped identify leaks that would otherwise have gone unnoticed for months.
On a wider scale, water companies carry out “district metered area” (DMA) monitoring. They measure how much water is supplied to groups of properties and compare this against expected consumption. If an area is losing more water than it should, engineers investigate, sometimes narrowing it down to specific supply lines.
While these systems are very effective at spotting unusual patterns, they can’t pinpoint exactly where the leak is. That’s where leak detection specialists like Harmuns come in — we trace the source with precision equipment designed for the job.
The signs of a hidden water leak in your home or business
Even if you don’t see water physically leaking, there are often subtle signs around the property that point to a problem. An unexplained increase in your water bill is one of the most common red flags. Another giveaway is the sound of running water when no taps or appliances are in use.
You may also notice damp patches appearing on walls or ceilings, a gradual drop in water pressure, or even a section of flooring that feels warm underfoot – a sign of a heating pipe leak. Outdoors, unusually green patches of grass or consistently damp ground can sometimes indicate a supply pipe problem.
In commercial settings, leaks may lead to higher maintenance costs or staff complaining about damp, uncomfortable conditions. Spotting these early makes a huge difference, as leaks left untreated only get worse with time.
The risks of leaving a leak untreated
Ignoring a leak flagged by your water company can be a costly mistake. Even a small underground leak can waste tens of thousands of litres a month, pushing up your bills and straining local water supplies. Ofwat estimates that around 3 billion litres of treated water are lost to leaks every single day in England and Wales – enough to fill over 1,200 Olympic swimming pools.
On top of the financial impact, hidden leaks can damage your property in ways that aren’t immediately obvious. Prolonged moisture weakens building materials, causes wood to rot, corrodes pipes, and encourages mould growth – all of which can lead to expensive repairs and even health issues. According to WaterSafe, unchecked leaks are one of the most common causes of internal damp and long-term structural damage.
For businesses, untreated leaks can also have legal and insurance implications. Many insurers expect leaks to be dealt with promptly, and failure to act can jeopardise future claims. That’s why acting quickly when a water company notifies you is always the best course of action.
How professional leak detection engineers trace hidden leaks
Finding the exact source of a leak takes specialist skills and equipment. At Harmuns, our engineers are WIAPS-approved (Water Industry Approved Plumbers Scheme) and, for heating-related leaks, fully Gas Safe registered.
We use a range of non-invasive technology to avoid unnecessary digging or disruption. Thermal imaging cameras can highlight hot water leaks under floors, while acoustic detectors listen for the faint sound of water escaping under pressure. Moisture meters help us locate dampness behind surfaces, and tracer gas testing allows us to track escaping gas through pipework with pinpoint accuracy.
These methods, along with pipe locators, steam generators, drones and endoscope cameras, mean we can often detect leaks within hours. Because our engineers carry this equipment on every job, we’re able to identify the problem and advise on the next steps in a single visit.
Preventing future leaks and protecting your property
Once a leak has been repaired, prevention is worth considering. Supply pipes made of older materials like lead or steel are more prone to failure, and if you’ve had one leak, others may follow.
Keeping an eye on your water meter when no water is being used is a simple check that can reveal if water is still escaping. Insulating external pipes helps reduce the risk of winter bursts, and arranging routine plumbing inspections is especially worthwhile in older properties.
Acting quickly at the first sign of damp, mould or unusual water usage is key. The sooner you intervene, the less chance there is of another unexpected call from your water company.
How Harmuns can help
If your water company has just told you there’s a leak, don’t panic — you’re not alone in dealing with it. Hidden leaks are more common than you think, and the key is to act fast before damage or costs spiral. At Harmuns, this is exactly what we specialise in: tracing hidden leaks quickly, cleanly and with the right technology to avoid unnecessary disruption.
Our WIAPS-approved and Gas Safe registered engineers have years of hands-on experience and carry the latest detection tools, from thermal imaging cameras to tracer gas kits. With a 5-star Google rating and top reviews on Trustpilot and Checkatrade, you can trust us to handle your leak with care and expertise. Save our number today — 01753 378569 — so if your water company ever says you’ve got a leak, you know exactly who to call.