ADI office open Monday–Friday, 7:30am–6:30pmAn urgent leak? Get help

School leak detection in Wales

Wales has no academy trusts, so its maintained school estate is managed by twenty-two local authorities and, for voluntary schools, by the dioceses.

6 engineers covering Wales

Part of ADI’s 23-engineer team across England, Scotland and Wales. This is the total for the Wales coverage area; individual county staffing and appointment availability are confirmed when booking.

ADI engineer coverage, checked 8 September 2026. See the counties served.

The school estate in Wales

Maintained schools in Wales
1,440

1,192 primary, 173 secondary, 31 middle, 39 special and 5 nursery, across 22 local authorities.

Source: Welsh Government, Address list of schools, April 2026 (opens in a new tab) (). This figure is restated annually; check the current edition.

Independent schools and pupil referral units
80 independent, 26 PRUs

Wales has no academy trusts, so the maintained estate is managed by the twenty-two local authorities and, for voluntary schools, by the dioceses.

Source: Welsh Government, Address list of schools, April 2026 (opens in a new tab) (). This figure is restated annually; check the current edition.

Welsh medium and bilingual schools
406

Schools categorised as Welsh medium or bilingual. It matters practically in one respect: site signage, notices and communications may need to be bilingual.

Source: Welsh Government, Address list of schools, April 2026 (opens in a new tab) (). This figure is restated annually; check the current edition.

Estate management structure
22 local authorities, plus the dioceses for voluntary schools

Wales has no academy trusts, so a school's condition budget and its supplier approval both run through the local authority, or through the diocese for voluntary aided schools.

Source: Welsh Government, Address list of schools, April 2026 (opens in a new tab) (). This figure is restated annually; check the current edition.

Water wholesalers serving Wales
Dŵr Cymru Welsh Water, Hafren Dyfrdwy

Dŵr Cymru Welsh Water covers most of Wales; Hafren Dyfrdwy covers parts of the north east and the mid Wales border. Schools in Wales buy retail services through the England and Wales non-household market.

Source: MOSL, Our members: trading parties in the non-household water market (opens in a new tab) ().

Ground and water conditions
Soft upland water across most of the country, former coalfield ground through the south Wales valleys, and high rainfall keeping groundwater levels up.

Source: Welsh Government, Address list of schools, April 2026 (opens in a new tab) (). This figure is restated annually; check the current edition.

School building programmes
Victorian and Edwardian schools across the valleys and rural counties, with the Welsh Government's 21st Century Schools programme replacing and remodelling a substantial part of the estate since 2011.

Source: Welsh Government, Address list of schools, April 2026 (opens in a new tab) (). This figure is restated annually; check the current edition.

The twelve UK regions arranged as a tile grid, each shaded by the number of open schools it contains, from the four national school registers.Scot2,427NI1,087NE1,220NW3,566Y&H2,421Wales1,440W Mid2,742E Mid2,293E Eng2,824SW2,617SE3,961Ldn3,111

The twelve regions arranged as a tile grid, shaded by open school count. Wales is outlined. Counts come from the four national school registers, not from an estimate.

What this means for a survey in Wales

The ground and water conditions above are the practical part. Hard water scales fittings and shortens the life of valves and mixers. Soft water is easier on scaling but less forgiving of some older metallic pipework. Shrinkable clay moves through a dry summer and pulls buried joints apart, and former coalfield ground settles differentially for decades after the workings closed.

None of that changes the sequence: measure at the meter, isolate to a branch, locate from the surface. It changes what we expect to find and where we look first.

Case studies from schools in Wales

None published yet. Rather than write a plausible-sounding example, this page says so. When ADI supplies a school in this region that is happy to be named, or happy to be described anonymously, it will appear here with the measured loss and what the repair involved.

Arranging a survey in Wales

Sources for this page

Last reviewed . How this site sources and dates its figures.

All twelve regions

0333 567 2619Emergency