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Leak detection for multi-academy trusts

Across a trust estate the cheapest leak to find is the one identified from consumption data before anyone reports it, by comparing every school's holiday baseline in one place.

The estate at a glance

Typical sites
Anything from five primaries in one town to ninety schools across several regions, with wildly different building eras inside one estate and no single set of drawings.
Typical pipework
Every generation at once. A trust that has taken on schools from three local authorities has inherited three sets of records, three standards and three levels of accuracy.
Who buys
Trust estates director or head of property, reporting to the CFO and the trust board
Budget route
School Condition Allocation for trusts above the threshold, Condition Improvement Fund bids below it
Working window
A rolling programme across the trust calendar rather than one summer window

Why a trust estate is a data problem before it is a plumbing problem

A single school notices a leak when the bill arrives or the ceiling stains. A trust can notice it earlier, because a trust has something a single school does not: a set of comparable buildings on comparable calendars. Put every school's August consumption in one column and the outlier is visible without anyone walking a site.

That is the whole argument for handling detection at trust level. The survey work is the same at each school. The saving comes from choosing which school to survey first, and from stopping a leak in its second month instead of its second year.

The estate profile a trust programme has to work around

Trust estates are heterogeneous by construction. Schools join at different times from different local authorities, and each arrives with whatever records that authority kept. Some come with a full asset register and an as-built drawing set. Some come with a photocopied site plan and an asbestos register.

  • Mixed building eras inside one estate, so no single detection method suits every school
  • Mixed metering: some schools on AMR with half-hourly data, some still on a manual quarterly read
  • Mixed water retailers, because the non-household market lets each school or the trust switch supplier independently
  • Records held in different places by different people, often the site manager rather than the trust
sound siteleaking siteband = the range each site moves through in a week; the lower edge is its floor
Weekly water consumption across a school year, comparing a sound site with a leaking siteEach site is drawn as a band between its weekly low and its weekly high. Both fall during holidays. The sound site's floor reaches close to zero in every holiday and at every weekend. The leaking site's floor never does, because a constant loss is added to every hour of the year, and the vertical distance between the two floors is the size of that loss.Summer holiday0255075100125this gap is the leakrunning every hour, all yearSepOctNovDecJanFebMarAprMayJunJulAugConsumption indexed to a term-time weekday = 100. Shaded columns are school holidays.

A school year of consumption for two schools in the same trust. Each band is the range that school moves through in a week. Both fall in the holidays; only one reaches the floor, and the distance between the two floors is the leak.

Which school in the trust is losing the water

In a trust of any size, one or two schools account for most of the unexplained loss. They are rarely the schools anyone would guess. The pattern that repeats is a mid-sized primary with a long buried run to a detached hall or nursery block, and a bill nobody has questioned because it has always been about that much.

  • Long buried runs to detached blocks, halls, nurseries and caretaker houses
  • Schools that joined the trust most recently, where the baseline is least understood
  • Sites with irrigation or a pitch supply, where summer consumption is expected to be high and a leak hides inside that expectation
  • Any school whose consumption did not fall during a closure period

Running detection as a programme rather than a series of emergencies

The sequence that works is: collect twelve months of consumption for every school, rank by holiday and weekend floor, survey the top of the list, repair, then re-baseline. It turns leak detection from a reactive cost into a measurable programme with a before and after figure per site.

Non-invasive methods matter more across a trust than at a single school, because a trust estate contains far more pre-1980 building than a new-build academy programme suggests. Locating from the surface avoids disturbing fabric that the trust, as duty holder, is responsible for managing.

One safeguarding position across every school

Trusts usually set a single contractor access standard and expect suppliers to meet it everywhere. That is easier for everyone, provided the standard is written down: DBS level, ID, escorting, sign-in, and what happens if an engineer needs to work in an occupied building.

Ask for the supplier's safeguarding policy once, at trust level, rather than at each school. Then the site manager's job on the day is to escort, not to assess.

Working across a calendar with several different holidays

Trusts spanning local authority boundaries, and trusts with independent or church schools, do not have one holiday. That is an advantage: a repair programme can move between sites across a longer window rather than compressing into six weeks in August.

The practical constraint is the trust's own approval cycle. A survey in the autumn term produces a report in time for the spring capital planning round, which is what gets the work funded for the following summer.

Which funding route the trust is actually on

This is the fork that decides how a leak repair gets paid for. For 2026-27 a trust needs five or more open schools and at least 3,000 pupils to receive a School Condition Allocation, with special school pupils counted at a 4.5 times multiplier. Trusts below that threshold bid into the Condition Improvement Fund instead.

Counting the current register against that rule, 526 of England's 2,148 trusts meet it. The rest are competing annually for capital, which is exactly why a dated survey report with a measured loss is worth more to a small trust than to a large one.

Where a leak is most often found in this setting
LocationWhy it happens here
The school in the estate with the oldest buildings and the least complete record setwhich is usually the one that was not converted with the founding group
Buried distribution mains on the larger secondary siteswhere a loss is a smaller share of a bigger bill and therefore hides longer
Washroom blocks and urinal controls across the primary schoolswhich produce a small loss per site and a large one per trust
Sites where a sub-meter was installed for an energy project and never read againSee the detection approach above.
Recently transferred schoolswhere the trust has inherited a leak it did not cause and does not yet know about
Generalised from common practice in this setting. Your own site may differ, and the survey starts at your meter rather than at this table.

What to do now

Take a meter reading tonight and another in the morning. If it has moved with the site closed, call and quote the figure; that single number shortens the survey and sets the scope before anyone attends.

Questions schools ask about this setting

Can you survey several schools in the same visit?

Yes, and it is usually the cheaper way to buy it. Schools within a reasonable radius can be surveyed on consecutive days by the same engineer, which removes repeated mobilisation and gives the trust one report written to one format.

We do not have half-hourly data for most of our schools. Can we still do this?

Yes. A manual meter read taken at the end of the day and again first thing the next morning gives you an overnight volume for that site, and that single number is enough to rank a school against its peers. Half-hourly data makes it faster, not possible.

Who owns the leak on a school we have just taken on?

Commercially that depends on the transfer terms and is a question for the trust's legal advisers. Practically the water is being lost now and the bill is arriving now, so the sequence is to find it, measure it, then argue about who pays with a report in hand rather than a suspicion.

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