Every town and postcode district in the coverage

Which towns get a page to themselves?

The towns with a page to themselves are Cardiff, Swansea, Newport, Wrexham and Bridgend, the largest post towns in the coverage by 2011 Census population.

Each of the five pages covers that town's own districts, where its water comes from and who answers for which pipe there, and Cambrian Leak Detection lists every other covered town further down.

Cardiff

CF3, CF5, CF10, CF11, CF14, CF15, CF23 and CF24, on the page for Cardiff leak detection.

Swansea

SA1, SA2, SA3, SA4, SA5, SA6, SA7, SA8 and SA9, on the page for leak detection in Swansea.

Newport

NP10, NP11, NP18, NP19 and NP20, on the page for Newport, south Wales leak detection.

Wrexham

LL11, LL12, LL13 and LL14, on the page for leak detection in Wrexham.

Bridgend

CF31, CF32, CF33 and CF35, on the page for Bridgend leak detection.

Which postcode areas and districts are covered?

The covered postcode areas are CF, SA, NP, LL, CH, SY and LD, with 173 districts between them, listed here by area and post town.

On this site the CH area is called Buckley and Deeside and the SY area Aberystwyth and Welshpool, after the biggest covered towns in each, because Royal Mail names both areas after towns outside the coverage. Newport in Pembrokeshire, district SA42, is listed under SA with the other Pembrokeshire towns.

Every district below is part of Cambrian Leak Detection's leak detection in every part of Wales.

• CF Cardiff
• SA Swansea
• NP Newport
• LL Llandudno
• CH Buckley and Deeside
• SY Aberystwyth and Welshpool
• LD Llandrindod Wells

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.

Is your water from Welsh Water or Hafren Dyfrdwy?

Your water comes from Welsh Water across most of the coverage and from Hafren Dyfrdwy in parts of north-east and mid Wales, which serves customers in Powys, Wrexham and parts of Flintshire, Denbighshire and Montgomeryshire; near the edge of its region, Hafren Dyfrdwy's own supply-area page says what to do.

Welsh Water provides water to over three million people across most of Wales and adjoining parts of England, and describes itself as a not-for-profit business with no shareholders.

Hafren Dyfrdwy, whose name means Severn Dee, was formed in 2018 and has 87,000 water customers and 22,000 wastewater customers. Its draft water resources plan says all of its supply area and all of its customers are in Wales.

This list does not show which company supplies each district; Hafren Dyfrdwy's Our supply area page answers that for its region. The company says it can be hard to tell whether a property on the edge of that region is inside it, and asks people there to contact it; for a property outside its region, it points to the Water UK website to find the supplier.

The company matters for a leak because the two draw the owner's line in different places: Welsh Water's part normally ends at the street boundary, and Hafren Dyfrdwy's at its external stop tap, which usually sits on the property boundary.

Why are some Welsh postcode districts missing from the list?

Some Welsh postcode districts are missing because the coverage is mainland only: the island districts of Anglesey, with Holy Island, and the 6 non-geographic districts are left out.

Anglesey, with Holy Island, takes in the districts LL58 to LL78, and Cambrian Leak Detection covers none of them.

Non-geographic districts had no residents at the 2011 Census, which is why none of them appears in the list above.

All five places with pages of their own are on the mainland, and each page is linked below.

• Cardiff leak detection for houses, flats and lettings
• Swansea leak detection for terraces, semis and flats
• Newport leak detection in south Wales
• Wrexham leak detection where Hafren Dyfrdwy supplies the water
• Bridgend leak detection for owners and landlords