Water Leaks: Whose Pipe, Whose Bill?
In short
Water leaks are Portsmouth Water's to fix up to your boundary and yours beyond it; the company pays £100 towards repairing your supply pipe, or £200 towards replacing it, if the work is done within 30 days of the leak being found.
Chalk & Cistern notes · checked and updated
On this page
Most leaks argue themselves into one of two piles: the water company's pipe or yours. The dividing line is usually the boundary of the property, often marked by a small stop tap cover in the pavement. Chalk & Cistern sets out where that line falls, what Portsmouth Water offers when the leak is on your side, and how a metered bill can be adjusted afterwards.
In brief
- Ofwat: water companies own the mains and the communication pipe to the property boundary; owners maintain the supply pipe, "including leak detection, repairs and replacement".
- Portsmouth Water says around 38% of leaks happen on customers' pipes and plumbing (Find it. Fix it.).
- The company contributes £100 to a supply-pipe repair or £200 to a full replacement, if done within 30 days of the leak being found.
- A leak allowance on a metered bill needs the supply pipe repaired within 60 days, and is offered once per property every 5 years.
- The allowance can reach back up to 12 months or two measured bills, whichever is longer, at Portsmouth Water's discretion.
- Portsmouth Water's minimum pressure standard is 1 bar at its stop tap.
Who is responsible for a water leak?
Responsibility for a water leak depends on which pipe is leaking: the company's up to the boundary, the owner's from there in. Ofwat's supply pipes page describes the communication pipe as carrying water from the main to the boundary of private property, and says a company stop tap, where fitted, normally marks the end of the company's pipework.
From the boundary onwards it is the supply pipe, which runs to the first fitting or stop tap inside the house, and then the internal plumbing. Ofwat says owners must maintain the supply pipes that are theirs. A supply pipe shared by several homes is shared between every owner on it.
Portsmouth Water's help page uses the same split: leaks on its pipes outside the boundary are its job; leaks on the underground supply pipe into your home, or inside it, are yours to repair. In a rented home, the Landlord and Tenant Act 1985, s.11 puts repair of the water installations on the landlord (see the landlords page).
How do you tell if you have a water leak?
The quickest way to tell if you have a water leak on the supply side is often the water meter. Portsmouth Water's Find it. Fix it. campaign says that if you have a meter, it "is often the best place to start", because water lost underground still passes through it.
Portsmouth Water points readers to a video for the meter check rather than printing the steps, so this site does not set out a procedure. The water meters page explains how to read the black digits, which record cubic metres, and why the red figures can be ignored.
Inside the house, the signs are usually plainer: damp patches, a dripping overflow, a stain on a ceiling. On a sealed heating system, Baxi's 400 Combi 2 user guide says that needing to re-pressurise regularly indicates a fault or leak; the boiler pressure page covers that case.
Weak flow is a separate question. Portsmouth Water's own check is to fill a 1-litre jug from the cold kitchen tap: under 7 seconds means the flow is fine.
What help does Portsmouth Water give with water leaks?
Portsmouth Water offers to survey the leak at no charge, plus two kinds of cash help with water leaks on a household supply pipe. Option one: it contributes £100 towards a repair, if the pipe is repaired within 30 days of the leak being identified. If the same pipe leaks again within 5 years, no further help is offered.
Option two: £200 towards replacing the entire supply pipe, again within 30 days. Both options exclude commercial, business, and council or housing association premises. Replacement can make sense for an old pipe, particularly lead: if you replace a lead supply pipe, Portsmouth Water says it will replace its own section to the main free of charge (the lead pipes page has the detail).
Repairs to underground pipe are plumbing work under the Water Supply (Water Fittings) Regulations 1999. The WaterSafe register lists approved plumbers trained in those regulations; the water regulations page explains what they cover.
What is a leak allowance?
A leak allowance is a reduction on a metered bill for water lost through a leak on your supply pipe. Portsmouth Water lists four conditions: you are on a meter, the leak is on your supply pipe, the loss was recorded by the meter, and the leak is repaired within 60 days of first being identified.
The limits matter as much as the conditions. One allowance is available per property in any 5-year period; it reaches back no further than a year, or two measured bills if that period is longer; it applies to external supply-pipe leaks only; and you must contact Portsmouth Water before starting repairs. Every allowance is at the company's discretion.
A dripping tap or a running toilet cistern indoors does not qualify. Metering is now compulsory across Portsmouth Water's area (moving to metering FAQ), and the wastewater company normally bases its charge on 92.5% of what the meter records, so water lost through the meter can show up on both parts of the bill.
What happens if a supply pipe leak is left?
If a supply pipe leak is left unrepaired, the water company can force the issue. Ofwat says a company may issue a legal notice under the Water Industry Act 1991, and if the owner does not fix the problem in the time allowed, the company can do the work and pass the cost on.
Leaving it also runs down the clock on Portsmouth Water's help: the £100 and £200 contributions need the work done within 30 days, the bill allowance within 60. Report the leak, ask for the survey, and keep a note of the date the leak was identified.
How do you report a leak in the street?
A leak in the road or pavement is reported to Portsmouth Water through the "Report a leak" link on its leaks, pressure and pipes page. Water from the main or communication pipe is the company's to fix.
Note where the water is coming up, how fast it flows and whether it is near a stop tap cover. If the leak turns out to be on your side of the boundary, the company's survey will say so and the options above apply. A burst inside the home is a different emergency: turn off your own stop tap first, as the burst and frozen pipes page explains.
Leak figures from Portsmouth Water
- 38%Share of leaks on private pipeworkPortsmouth Water, Find it. Fix it.
- £100Towards a supply-pipe repair within 30 daysPortsmouth Water
- £200Towards replacing the whole supply pipe within 30 daysPortsmouth Water
- 60 daysRepair deadline for a metered leak allowancePortsmouth Water
- 1 barMinimum pressure at the company stop tapPortsmouth Water
| Pipe | Runs from and to | Responsible |
|---|---|---|
| Water main | Under the road | Portsmouth Water |
| Communication pipe | Main to the boundary or company stop tap | Portsmouth Water |
| Supply pipe | Boundary to the first stop tap or fitting inside | Property owner |
| Shared supply pipe | Boundary to several homes | Every owner on it, jointly |
| Internal plumbing | Inside the home | Owner; landlord in a rented home |
Where these figures come from
This page uses Ofwat's supply pipes page, Portsmouth Water's leaks, pressure and pipes page, its Find it. Fix it. campaign page and metering FAQs, Baxi's 400 Combi 2 user guide (2023), the Landlord and Tenant Act 1985 and the WaterSafe register, all read in October 2026. Portsmouth Water's leakage code of practice is marked as under review and its leak leaflet could not be opened, so neither is used. Left out: a step-by-step meter leak test (no written primary source), plumbers' prices and leak-detection costs.
Further questions
Does home insurance cover a leaking supply pipe?
That depends on the policy, and none was read for this page. Check the policy wording for underground services before arranging a repair, and keep the date the leak was found for Portsmouth Water's 30-day and 60-day limits.
Who pays if the leak is under a neighbour's garden?
If the pipe serves only your home, it is your supply pipe wherever it runs. If it serves several homes, Ofwat makes it a joint duty of the owners on that pipe.
Can a tenant claim the leak allowance?
The allowance attaches to the metered account and the property. A tenant who pays the water bill can ask Portsmouth Water, but repairs to the supply pipe in a rented home fall to the landlord under the 1985 Act.
Does the £200 contribution apply to flats in a council block?
No. Portsmouth Water excludes commercial, business, and council or housing association premises from both contributions.
Will the water company dig up my drive to find a leak?
Its survey locates the leak; who digs depends on whose pipe it is. On your supply pipe, the repair and any reinstatement are yours to arrange, with the contribution towards the cost.
Is low water pressure a sign of a leak?
It can be one cause among several. Portsmouth Water's minimum is 1 bar at its stop tap, and its jug check is a litre from the cold kitchen tap in under 7 seconds; if flow falls short, ask the company before assuming a leak.
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