The decision to use the money from reserves was taken by the full council.
Conversion of the site, in Hurst Road, will include repairs to the roof, the installation of energy efficient lighting and heating, and more specific items such as a vehicle inspection pit, drainage and workshop equipment.
It will be used by the smaller 12-tonne vehicles rather than the larger waste lorries.
Jay Mercer, cabinet member for environmental health, recycling and waste, said the council was submitting an application for funding from the Department for Environment, Food and Rural Affairs (Defra). If successful, it will be used to help cover the cost.
The council is required to start food waste collections across the district by spring 2026.
Should planning permission be received to change the use of the building, conversion work will start as soon as possible so that it will be ready for the service roll-out.
Questions were asked about why the maintenance depot could not be placed on land at the recycling centre in Hop Oast.
Tory councillor for West Chiltington, Thakeham and Ashington Philip Circus pointed out that when the new unitary authority takes up power, both the tip and the depot will be in common ownership.
He added: “I would have thought we could start to think in a more coherent and collective way about these things.
“Because, without any doubt, to consolidate all these facilities on the one site would be the most ideal situation.”
Given traffic levels along Hurst Road, Mr Circus asked if the situation could be looked at again once the depot opens, to see if any problems arise.
Mr Mercer said the original plan had been for a ‘relatively straightforward and simple arrangement to further share the Hop Oast site’.
But this didn’t prove possible.
He added: “We can all speculate about what might happen in the future. At the end of the day, we do have a statutory responsibility to deliver the food waste collection.
“In order to do that, the key thing is having immediate availability of spare capacity when vehicles either break down or need to go for maintenance.
“This is a critical facility for us.”
Mr Mercer did not commit to a review but advised that the situation would inevitably be looked at by the unitary authority.