In This Guide
How do you know the leak is underground?
An underground leak rarely shows itself directly, so it is usually spotted from its side effects. The common signs are a patch of ground that stays damp or unusually green in dry weather, a drop in water pressure, a water bill that has climbed for no obvious reason, or the faint sound of running water when everything in the house is switched off.
The quickest way to confirm it is the water meter test: turn off every tap and appliance, read the meter, wait 30 minutes without using any water, then read it again. If the reading has moved, water is escaping somewhere on the supply. Our guide to checking for a water leak at home walks through this step by step, and how to track and trace a water leak accurately covers narrowing down where it is before anyone digs.
Who is responsible for an underground water pipe?
This matters, because it decides who pays. The supply pipe that runs from the external stop tap into your home is the homeowner’s responsibility to maintain and repair. The water main in the street, and the pipework up to and including the external stop tap, belongs to your water company, which in London is usually Thames Water.
So if the leak is on the private supply pipe between the boundary and your house, it is your responsibility, though your buildings insurance may help with the cost of finding and accessing it. If it is on the water company’s side, report it to them.
How is an underground leak found and fixed?
The mistake to avoid is digging first and looking second. Excavating along the line of a pipe hoping to find the leak causes unnecessary damage and often misses it. The right sequence is to locate precisely, then access only that spot.
0800 Homefix locates underground leaks using acoustic listening equipment and tracer gas, which pinpoint the failure point to within centimetres before any ground is opened. Once the leak is confirmed, the pipe is exposed and either repaired with a clamp or the damaged section is cut out and replaced. On older or repeatedly failing supply pipes, replacing or relining the run can be more cost-effective than patching. You can see the full service on our underground leak detection and water leak detection and repair pages.
Can you fix an underground water pipe yourself?
For a buried supply pipe, realistically no. Locating the leak needs specialist equipment, and any work on the supply pipe should be carried out by a qualified, WaterSafe-registered plumber to keep your drinking water safe and compliant. What you can and should do first is turn off the water at the internal stop tap to limit the loss and any damage while you arrange help. Guessing at the location and digging yourself usually costs more than it saves.
Will insurance cover it?
Often, yes, at least for the finding and accessing. Most UK buildings insurance policies include trace and access cover, which pays to locate a hidden or underground leak and reinstate the surface afterwards, up to your policy limit. It is worth checking your policy before assuming you face the full cost. Our guides on what trace and access costs and whether trace and access is standard on home insurance explain how the cover works and how to claim.
How 0800 Homefix fixes underground leaks
0800 Homefix covers London and the South East, and underground supply leaks are core work for us. An engineer locates the leak accurately before any excavation, confirms whether it is on your side of the boundary, and carries out the repair, in most cases within the same visit. Where the work supports an insurance claim, we provide a written report your insurer can use.
On cost, 0800 Homefix charges as the first hour of labour, paid in advance, with any further investigation, access, or repair work quoted and agreed with you before it begins. For current rates, see our rates page. Our labour is guaranteed for 12 months, and any parts we fit are covered by the manufacturer’s 12-month guarantee.
Frequently Asked Questions
How do I know if my underground water pipe is leaking?
Look for ground that stays damp or greener than the area around it, a drop in water pressure, an unexplained rise in your water bill, or running water you can hear when everything is off. Confirm it with the water meter test.
Who is responsible for a leaking underground pipe?
The supply pipe from the external stop tap into your home is the homeowner’s responsibility. The main in the street and the pipework up to the external stop tap belong to the water company, which in London is usually Thames Water.
Can I repair an underground water pipe myself?
It is not a DIY job. Locating the leak needs specialist equipment, and work on the supply pipe should be done by a WaterSafe-registered plumber. Turn off the internal stop tap to limit damage and arrange a professional.
Does insurance cover an underground water leak?
Most buildings insurance policies include trace and access cover, which pays to locate and access a hidden or underground leak up to your policy limit. Check your policy schedule for the cover and limit before instructing anyone.
How is an underground water leak repaired?
The leak is located precisely with acoustic and tracer gas equipment, the pipe is exposed at that point, and it is either clamped or the damaged section is replaced. Badly worn supply pipes may be replaced or relined instead of patched.
Helpful resources
- WaterSafe: find an approved plumber qualified to work on supply pipes.
- Consumer Council for Water: independent guidance on water supply pipe responsibility and costs.
Spotted Any of These Warning Signs?
Think you have an underground water leak? 0800 Homefix locates and repairs buried supply leaks across London and the South East with no unnecessary digging and a written report for your insurer where you need one, seven days a week, 365 days a year.
Editorial note: This article is intended as a general homeowner guide. All plumbing work on supply pipes should be carried out by a qualified, WaterSafe-registered plumber. If you suspect a gas leak, leave the property immediately and call the National Gas Emergency Service on 0800 111 999.
