The IRS states that real estate taxes are only deductible by a taxpayer that is legally required to pay the taxes AND actually pays them.
If the trust requires you to pay them, then you can deduct them.
You can deduct real estate/property taxes that you pay for the property that you own. If you are the beneficiary of the Irrevocable Trust, then you own the home and can deduct the taxes.
If the property taxes were, in fact, paid by the irrevocable trust, then certainly, the trust can take a deduction for taxes paid on its Form 1041 tax return. It will constitute a reduction of Distributable Net Income (or of taxable income).
Alternatively, and depending on the language of the trust instrument, the property taxes paid by the trust could instead by "passed through" to you via a Schedule K-1. In that instance the trust would not claim the property taxes paid deduction, but you could do so on your personal income tax return (if the total of your Itemized deductions exceeds your Standard deduction, that is).
The point here being that the same deduction for the same dollar of property taxes paid is allowed to only one taxpayer -- the trust, or a beneficiary -- and both cannot claim the same tax deduction for the same dollar amount. Although, in theory, and again depending on the language of the trust, the tax deduction benefit could be between taxpayers on a split 50% / 50% for example.
