How to Report a Leak to Thames Water (And What They'll Actually Fix)

Reporting a leak to Thames Water is straightforward, but a lot of Londoners either report a leak that was never the company's to fix, or wait patiently for a repair that is actually their own responsibility. Getting it right saves everyone time: the water company can prioritise the leaks that are genuinely theirs, and you can move quickly on the ones that are yours before the damage and the wasted water mount up.

This guide explains how to report a leak to Thames Water, what they will and will not repair, roughly how long it takes, and — importantly — what to do when it turns out the leak is on your private pipework. We are an independent London leak detection company and are not affiliated with Thames Water; think of this as a plain-English map of the process from both sides of the boundary.

How do I report a leak to Thames Water?

Thames Water provides ways to report a leak directly. The most common route is their website, which has an online leak reporting form where you describe the location and what you can see, and they also operate a dedicated leak-reporting phone line for the region. When you report, give as much detail as you can: the exact location, whether the water is clean or dirty, how much is flowing, whether it is affecting the road or a footpath, and whether your own water pressure has changed. Photographs help.

Reporting is worth doing even if you are not certain whose leak it is, because a visible leak in the street, at a stopcock cover in the pavement, or at a hydrant is very likely theirs, and prompt reports help stop water being wasted. Do not attempt to open or interfere with the company's boundary apparatus in the street yourself.

• Report via Thames Water's website leak form or their leak-reporting phone line.
• Describe the exact location, the amount of water, and whether it is clean or dirty.
• Note any change in your own water pressure and include photos if you can.
• Do not tamper with stopcock covers, hydrants or apparatus in the street.

What will Thames Water repair, and what falls to me?

Thames Water repairs leaks on the water main and on the communal pipe up to the boundary of your property, as part of running the network. If the leak is on that side of the line — in the road, the footpath, or at the boundary stop valve — reporting it is the right and only action you need to take, and they will schedule a repair.

What they will not routinely repair is a leak on your private supply pipe (the buried pipe from the boundary into your home) or anything inside the property. Those are the owner's responsibility. Water companies have at times offered a free or subsidised first repair on a customer's external supply pipe, but availability and conditions change, so check directly with Thames Water rather than relying on it. If the leak is internal or on the buried supply pipe under your land, the practical route is independent detection and repair.

How long does Thames Water take to fix a reported leak?

Response times vary with how serious the leak is and how much water is being lost. A large leak flooding a road or threatening property is treated as a priority and attended quickly, while a small, slow weep at a pavement stopcock may be logged and scheduled for later, sometimes weeks out, because the company balances thousands of leaks by severity. That prioritisation is reasonable across a network, but it is cold comfort if the leak is affecting you and turns out to be borderline.

This is one reason it matters to establish early whether the leak is even theirs. If your checks show the escape is on your side of the boundary, waiting for Thames Water is waiting for a repair that is not coming, while the meter runs and the water spreads. The sooner you know which side it is on, the sooner you can act on the right one.

How do I check whether the leak is mine before I wait?

Two quick checks settle it in most cases. First, with all water off inside the house, close the outside boundary stop valve near the pavement; if the leak slows or stops, it is on your side. Second, turn off every tap and appliance and watch your water meter; continued movement means water is escaping on the metered, private side, which is your responsibility. If both point to your side, there is little value in waiting on the company — the leak is yours to find and fix.

The location of surfacing water is only a weak clue on its own, because water travels underground before it emerges. But combined with the stop-valve and meter tests it usually gives a clear enough answer to know whether to wait for Thames Water or arrange your own detection. For the full picture of the responsibility split, see our guide on who is responsible for a Thames Water leak.

• Close the boundary stop valve with the house water off — does the leak slow?
• Watch the meter with everything off — is it still turning?
• Both pointing to your side means it is yours, so do not wait on the company.

The leak is on my side — what next?

If the checks show the leak is yours, act quickly. A buried supply pipe leak wastes water and can undermine drives and foundations; an internal leak damages plaster, floors and joists. The efficient route is precise detection to find the exact spot, then a targeted repair, rather than excavating or opening up on a guess. Our engineers cover all 33 London boroughs, work on a no find, no fee basis for detection, and provide a written report you can use both to request a Thames Water leak allowance on your bill and to support an insurance claim for any damage.

So the full sequence is: report anything that looks like the company's leak; run the stop-valve and meter checks to confirm which side it is on; wait for Thames Water if it is theirs; and if it is yours, get it located and fixed without delay, then reclaim what you can on the bill. Reporting and detecting are not competing steps — they are how you make sure the right party fixes the right leak, fast. If it is an active emergency, our emergency plumber and water leak repair services can attend the same day.