Who is responsible for the water supply pipe to my house?

The property owner, from the boundary stop tap to the internal stopcock. The water company is responsible for the communication pipe from the main in the street up to that boundary stop tap. CCW and the water companies publish the split, and it is the reason a supply leak letter is addressed to you.

Can you find a supply pipe leak without digging up the garden?

Finding it, yes — that is the point of tracing the route and locating acoustically or with tracer gas before any excavation. Repairing it means opening the ground at one point. What we avoid is the trench along the whole run that comes from digging on an assumed route.

Should I repair my lead supply pipe or replace it?

Replace it, in almost every case. Lead work-hardens and splits at bends, so a patch tends to be followed by another split elsewhere, and each repair means excavating again. A new MDPE run usually improves flow as well as removing lead from the drinking water supply.

Will my water company pay for a leak on my supply pipe?

Not for the repair — that is yours. Many suppliers do operate a leak allowance that can credit some of the water lost once the leak has been repaired, subject to their own conditions and evidence. Ask your supplier what theirs requires before the work, because some want notice in advance.

How do I know the leak is outside and not under my floor?

Turn everything off, close the internal stopcock and watch the meter. If the meter still turns with the stopcock shut, the loss is on the buried run outside. If it stops, the leak is inside the building.

Repairs

Mains and Supply Pipe Repair in London

From the boundary stop tap to your internal stopcock, the supply pipe is the property owner’s responsibility, not the water company’s — we locate the leak on it, repair or replace the run in MDPE, and put the drive, path or lawn back.

The Leak Fix London van outside a London property

What the job includes

Meter test to confirm the loss is real and to place it inside or outside the building
Tracing of the buried route from the boundary stop tap to the property entry point before excavating
Location by ground microphone, or by tracer gas on a drained supply where the ground or depth defeats acoustics
Single-point excavation at the confirmed location rather than a trench along the run
Repair of the failed section, or full replacement in new MDPE from boundary to internal stopcock
Moling in place of open-cut trenching where the ground and the route allow it
Pressure test of the new or repaired run before the ground is closed
Backfill, compaction and reinstatement of block paving, slabs, concrete, tarmac, turf and planting

No find, no fee · £150 per hour. The rate is fixed before we attend and does not rise for a difficult property, an awkward access or an evening visit. The total depends on how long the job takes; the rate cannot change.

Where the water company's pipe stops being their problem

There are two pipes and one boundary. The communication pipe runs from the water main in the street to the boundary stop tap, usually in a small chamber in the pavement or just inside the front boundary. That pipe belongs to the water company. The supply pipe runs from that stop tap to your internal stopcock, and it belongs to the property owner — under your front garden, under your drive, under your path, under the floor of the house.

That is why a letter telling you there is a leak on your supply arrives addressed to you and not to a utility. CCW, the statutory consumer body for water, and Thames Water both publish the boundary and the ownership split. What your supplier can and cannot require of you, and the notice they send, is covered under Thames Water.

Two practical consequences. A supply pipe leak is metered on your account if you are on a meter, so it is costing you money continuously — see water bills and meters. And nobody else is going to fix it.

How we find a leak on a buried supply

Prove it at the meter. Everything in the property is turned off, the meter is read, and it is read again after a set interval. A meter that keeps turning with nothing running is a live loss. If it stops when the internal stopcock is closed, the leak is inside; if it keeps turning, it is on the buried run outside. That single test decides where the whole job happens. The meter turning with everything off walks through it.
Trace the route. A buried supply rarely runs where anyone assumes. The line is traced from the boundary chamber to the entry point before a spade touches the ground, because digging on an assumed route is how a driveway gets opened twice.
Locate the escape. On a pressurised plastic or metal supply, ground microphones pick up the escape noise at the surface. Where the ground is noisy, the pipe is deep or the run passes under a slab, we isolate and drain the supply and use tracer gas instead, which surfaces through soil, hardcore and block paving as readily as through screed.
Mark and excavate at one point. A supply pipe repair should mean one hole, not a trench along the length of a garden.

What we find on London supply pipes

Lead. Very common in pre-war stock. It splits at work-hardened bends and at old wiped joints. We do not treat a patch on a lead supply as a finished job — WaterSafe sets out why lead pipework is replaced rather than maintained in a drinking water supply.
Alkathene. The black polyethylene used from the 1960s to the 1980s. It goes brittle with age and cracks longitudinally, often near a fitting.
A bad marriage of materials. New MDPE joined to old lead or alkathene with an adaptor that was never designed for the pairing. One of the most frequent failure points we dig up.
Pipe laid too shallow. A supply under a driveway that was resurfaced without anyone checking the cover depth gets loaded by every car and freezes in a hard winter.
Damage from other trades. A fence post, a drainage run, a new soakaway or a cable trench put straight through the supply. The leak often appears months later once the ground settles.
The internal stopcock itself. Sometimes the "buried leak" is a weeping stopcock under the kitchen sink, which is a ten-minute job. A leaking stopcock covers it.

Repair, or replace the run

A single clean failure on a sound MDPE supply is repaired in place: the section is cut out and a new length joined in, then pressure tested before the hole is backfilled.

A lead, alkathene or repeatedly patched supply is a different decision. Replacing the whole run in new 25mm MDPE from the boundary stop tap to the internal stopcock ends the sequence of repairs, usually improves the flow rate at the tap noticeably, and takes lead out of your drinking water. Where the ground allows, the new run can often be moled rather than trenched, which means two small excavations rather than a trench across the garden. Where it has to be open-cut — under a concrete drive, through a paved front garden, around existing services — we say so before starting, and we price putting the surface back as part of the job rather than leaving you with a scar.

Putting the ground back

This is the part that separates the job done properly from the job that leaves a patch of mismatched tarmac at your gate for the next decade. Our own reinstatement team backfill and compact in layers, reinstate block paving with the original blocks lifted and set aside, patch concrete and tarmac, relay slabs, and make good turf and planting where the run crossed a lawn or a border. If a surface cannot be matched — a discontinued block, a resin drive — you are told before the ground is opened, not after.

When it is not your pipe, and not your bill

Do not start digging before these are ruled out:

The leak is before the boundary stop tap. Then it is the water company's communication pipe and their cost. Report it to your supplier and let them attend.
A wet patch in the street or pavement, not on your land. Same answer.
A high bill with a still meter. If the meter does not move with everything off, you do not have a supply leak, whatever a letter says. Something else is driving the bill.
A shared supply. Older terraces sometimes have one supply pipe serving several houses. Who pays is then a shared question, and it is worth establishing before one neighbour commissions a replacement alone.

Most suppliers also operate a leak allowance that can credit the water lost through a supply pipe leak once it has been repaired, subject to their own conditions. Ask your supplier what theirs requires before the repair, because most want evidence and some want notice.

What it costs

Charged at our hourly rate, fixed before we attend, plus materials and any specialist ground reinstatement. The rate cannot rise once agreed. The total on an external supply depends heavily on the ground: a moled run across a lawn and an open-cut across a concrete drive are very different amounts of work, and we will not pretend to know which yours is before the route is traced. If we cannot find the leak, you do not pay for the time we spent looking. Terms on the pricing page.

Frequently asked

Who is responsible for the water supply pipe to my house?: The property owner, from the boundary stop tap to the internal stopcock. The water company is responsible for the communication pipe from the main in the street up to that boundary stop tap. CCW and the water companies publish the split, and it is the reason a supply leak letter is addressed to you.
Can you find a supply pipe leak without digging up the garden?: Finding it, yes — that is the point of tracing the route and locating acoustically or with tracer gas before any excavation. Repairing it means opening the ground at one point. What we avoid is the trench along the whole run that comes from digging on an assumed route.
Should I repair my lead supply pipe or replace it?: Replace it, in almost every case. Lead work-hardens and splits at bends, so a patch tends to be followed by another split elsewhere, and each repair means excavating again. A new MDPE run usually improves flow as well as removing lead from the drinking water supply.
Will my water company pay for a leak on my supply pipe?: Not for the repair — that is yours. Many suppliers do operate a leak allowance that can credit some of the water lost once the leak has been repaired, subject to their own conditions and evidence. Ask your supplier what theirs requires before the work, because some want notice in advance.
How do I know the leak is outside and not under my floor?: Turn everything off, close the internal stopcock and watch the meter. If the meter still turns with the stopcock shut, the loss is on the buried run outside. If it stops, the leak is inside the building.