Schools across County Durham will face money troubles if action is not taken to balance their books.
The forthcoming financial difficulties were flagged amid a council overspend of almost £15m and calls for urgent government help at a Durham County Council cabinet meeting this week.
Piggy banks will need to be raided for an extra £10m as energy costs and pay awards wiped out council chiefs' earlier budget calculations.
The council's original budget for the 164 schools it maintains had been £255m for the year, most of it from central government funding.
But the amount needed from reserves has now soared from £7.3m to almost £17.7m.
Councillor Richard Bell, deputy council leader and cabinet member for finance, said maintained schools faced pressures which far outstripped budget assumptions, up by £10m from initial budget estimates.
He said: "Undoubtedly there will be more schools that will find it difficult to balance their budgets next year unless additional funding is forthcoming.
"The same reasons driving the council's overspend - the combination of higher than budgeted pay awards and inflationary pressures on energy and other contracted services - are manifesting themselves in schools and resulting in a forecasted significant increase in the utilisation of retained schools' balances if, as expected, no further funding is to be made available this year.
"If unsupported, many schools will face significant challenges in setting balanced budgets, both maintained and academy schools."
He said he had highlighted the issue in a letter to the Prime Minister and Chancellor.
He added: "We must continue to support but also challenge our schools to properly manage their budgets and ensure that school leadership teams, including their governing bodies, are living within their means and ensuring that they balance their books, which can mean difficult decisions having to be made."
A council report shows schools' gas costs are up 96% from 2021-22, electricity up 63%, with rising inflation and no additional grants coming in.
An extra £16.7m is needed for employees, £10.3m of which is for higher pay awards for teachers and support staff, with £2.7m more to be spent on energy, repairs and maintenance and £2.6m more on supplies.
All this is offset by an £11.8m rise in income from grant funding, fees and charges.
Resources director Paul Darby said schools faced "significant unbudgeted budget pressures".
He said there were seven schools with deficit balances totalling £3.689m - two more schools with such shortfalls than the previous year.
He said five of the schools set balanced budgets for 2022-3 where they would recover the money, while the remaining two - Wellfield School and Durham Community Business School (DCBC) - were granted permission to set a deficit budget and stay in the red.
DCBC will have its deficit of between £570,000 and £650,000 written off when it joins a multi-academy trust next year.
Mr Darby added: "Our schools were budgeting this year to use £7.3m of their balances. This is not an unusual position at this stage.
"What is different this year is the significant volatility in terms of inflationary pressures on those schools' budgets."
A forecast "indicates a significant deterioration in financial outlook for our schools as a result of the expected teachers' pay award, non-teaching staff pay award and price inflation, most notably energy price inflation".
He said: "At this stage the use of retained balances is expected to more than double to around £17m this year.
"Without corrective action, many more schools will find it difficult to balance their budgets next year."
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