Cardiff leak detection for houses, flats and lettings
Leak detection in Cardiff finds hidden leaks on the water pipes, heating systems and supply pipes of the city's houses, flats and let homes, in every district whose post town is Cardiff. All of them are within Cambrian Leak Detection's coverage.
- Cardiff
- Caerdydd
What counts as Cardiff for leak detection on this site?
Cardiff, for leak detection on this site, means the 8 districts whose post town is Cardiff: CF3, CF5, CF10, CF11, CF14, CF15, CF23 and CF24.
- CF3
- CF5
- CF10
- CF11
- CF14
- CF15
- CF23
- CF24
Contains OS data © Crown copyright and database right 2026. Contains Royal Mail data © Royal Mail copyright and database right 2026. Source: Office for National Statistics licensed under the Open Government Licence v.3.0.
Cambrian Leak Detection also works in the towns around the city that have post towns of their own, Penarth, Barry, Caerphilly and Pontyclun among them, and every one of their districts is on the full list of covered towns.
Who pays when water passes between Cardiff flats or a let home?
Who pays when water passes between Cardiff flats or into a let home depends on where it starts: the pipe or fitting that leaks is its owner's responsibility, and in a rented home the landlord must keep the water and heating installations in repair, including installations elsewhere in the building that serve the flat where the landlord owns, controls or has an interest in them.
Flats and lettings weigh more heavily in Cardiff than anywhere else Cambrian Leak Detection has a page for. Census 2021 put 20.2% of households in the Cardiff council area in purpose-built flats and 24.3% in homes rented privately, the highest shares of both among the five places, so more of the city's homes sit above, below or beside another household, or belong to a landlord.
The Renting Homes (Wales) Act 2016 sets out the landlord's side. For a secure contract, a periodic standard contract or a fixed term standard contract made for less than seven years, section 92(1) makes the landlord keep the structure and exterior in repair and keep the home's service installations in repair and proper working order, and an installation for water, sanitation, space heating or heating water counts as one. Section 92(2) reaches past the flat's own walls: where the home is only part of a building, the landlord must keep any installation that directly or indirectly serves it “in repair and proper working order”, if it sits in a part of the building in which the landlord has an estate or interest, or the landlord owns or controls it.
Tenants are contract-holders under the Act, and Welsh Water suggests they speak to the landlord straight away, since the repair may fall to the landlord to arrange.
Where nobody rents, Welsh Water's rule is that every pipe and fitting indoors is the owner's to repair. Who pays for the ceiling of the flat below is a separate matter, and it is one for the insurers involved to settle. What Cambrian Leak Detection brings to it is the position of the leak, recorded for the insurer, and the guide to trace and access records for insurers sets out what that record holds.
Which reservoirs and mains bring water to Cardiff?
Cardiff's water comes from high-level reservoirs and a low-level one: Cantref (1892) and Llwyn-on (1926) in the Taff Fawr valley were built to supply Cardiff, Welsh Water describes a main running south from its Llwynon treatment works into the city, and Llandegfedd Reservoir, Welsh Water says, has an important role in supplying more than 600,000 people across Cardiff, Newport, parts of Monmouth and surrounding areas.
Coflein's records give the two Taff Fawr dates exactly. Cantref Reservoir was inaugurated on 14 September 1892, and Llwyn-on Reservoir was inaugurated in June 1926 and fully commissioned in May 1927.
In Welsh Water's water resources plan, the Taff Fawr and Taff Fechan reservoirs are the high-level storage of its South East Wales system and Llandegfedd is the key low-level reservoir. The city sits in the company's Southeast Wales region, which serves nearly 1.6 million people living mainly in Cardiff, Newport and the South Wales valleys.
All of that, from the dams to the main under the road, is Welsh Water's network, and the company says it will always repair the pipes it owns as quickly as possible. A Cardiff household's share of the pipe starts later, at the street boundary covered in the last section of this page.
Which kind of leak investigation does a Cardiff property need?
A Cardiff property needs the investigation that matches where the water is escaping: the water pipes inside, the heating circuit, the underground supply pipe, or a trace and access search for an insurance claim.
The panel gives the Cardiff council area's homes as Census 2021 and the Valuation Office Agency count them; the council area is larger than the post town, and terraced and semi-detached houses are its two commonest kinds of home.
- Homes in the Cardiff council area, 2021
- In 2021, Cardiff council area households lived 29.6% in terraced houses, 29.7% in semi-detached houses, 14.1% in detached houses and 5.0% in converted or shared houses; 58.0% owned their home and 17.2% rented socially.
- Dwellings built before 1919
- In the Cardiff council area, 23.7% of dwellings were built before 1919: 39,780 of 168,180 at 31 March 2026.
Sources: Office for National Statistics, Census 2021 TS044 Accommodation type; Office for National Statistics, Census 2021 TS054 Tenure; Valuation Office Agency, Council Tax: stock of properties, 2026.
Pipe leak detection in a Cardiff flat
A ceiling stain may begin in the room overhead, and in a block of Cardiff flats that room can belong to another household; the search traces that water to the pipe it is escaping from.
Central heating leak detection
A Cardiff boiler whose gauge falls again after every top-up is losing water somewhere on its sealed circuit, which may be a radiator valve, a pipe under the floor or the boiler itself.
Supply pipe leak detection
The buried pipe from the street to a Cardiff house is the owner's even where it crosses next door's garden, and a metered bill that rises with no extra use is one sign of a leak along it.
Trace and access for a Cardiff insurance claim
When a leak in one Cardiff flat marks the ceiling of the flat below, the search gives the insurers involved a record of where the leak is and how it can be reached.
Where does Welsh Water's pipe stop outside a Cardiff home?
Welsh Water's pipe normally stops at the boundary of the street where its main is laid; from there the supply pipe into a Cardiff home is the owner's to look after, including any stretch that runs under a neighbour's land.
Welsh Water calls its own stretch, from the main to that boundary, the communication pipe, and its leaks booklet adds that the line falls at the street boundary in most cases, though not always.
For household customers, Welsh Water will try its best to pinpoint a leak on the external supply pipe, as long as it can establish where the pipe runs, the leak is large enough for its equipment to pinpoint, and the leak is not under the house, a wall, a shed, a garage or any other structure.
Its Leak Support Scheme is kept for customers who own the home they live in, so a Cardiff landlord with a leak under a let house arranges the repair without it.
Everything from the street boundary inwards is where Cambrian Leak Detection works, and the home page covers its leak detection in Wales as a whole.
Water escaping in the road, or from a burst main, is on Welsh Water's side of the line, so the step there is to report it on Welsh Water's Report an issue page, which takes reports online at any hour.