Landowners Malcolm, Daniel and Richard Payne want to build the homes on the outskirts of the village of Great Totham.
However, the local planning authority, Maldon District Council, has opposed the proposals.
Against the advice of planning officers, the council refused to grant planning consent for the development in 2016.
Councillors said that building homes outside the village's boundary would harm the character and appearance of the countryside.
But the Paynes' successfully appealed the refusal and outline planning permission was granted in March 2017.
However, the council then pointed to the 35-year-old planning agreement which it said meant that the 1.83-hectare site off Hall Road could never be developed.
The site was once part of a larger property owned by local cricket fan, Tom Martin, said judge Peter McCrea.
And, after he died, the executors of his estate were granted planning permission to build six new homes on part of his land.
As a quid pro quo for that, Martin's heirs donated a cricket field to Totham Parish Council, the Upper Tribunal heard.
And, crucially, the executors signed up to the planning agreement in 1984 which banned construction of any permanent, non-agricultural, buildings on the site.
Again against its planning officers' advice, the council refused to waive the building restriction at a meeting in May last year.
Faced by the prospect of their plans being stymied, the Paynes applied to the Upper Tribunal to lift, or modify, the building restriction.
According to the judge’s ruling, the applicants sought to discharge a covenant entered into under the planning agreement made "under section 52 of the (now repealed) Town and Country Planning Act 1971."
Upholding their application, Judge McCrea said the position on the ground had greatly changed since 1984.
Of the 30 homes proposed by the Paynes, 12 of them would be affordable, he added.
The area's "pressing need" for more new homes , especially social housing, "tipped the balance" in favour of the development.
And the judge ruled that the 1984 agreement was nowadays of "no substantial value or advantage" to the council.
He added: "It cannot be of substantial value or advantage to the council to resist a reasonable use of the land for a development for which outline planning permission has been granted, and which would, if permitted, go towards meeting the district's housing need.
"I am also mindful that at each stage of advising its elected members, the council's planning officers recommended approval of the development.
"The council's evidence is completely at odds with that advice, and I place little weight upon it."
Judge McCrea amended the 1984 agreement so as to enable the Paynes to press ahead with the development.
And refusing to award the council compensation, he ruled: "Far from sustaining a loss or disadvantage as a result of the modification, the council would benefit from the development taking place."