McCarthy and Stone plans to build retirement homes on the 0.94 acre site, off Crown Street, and has notified Stone Town Council of its intentions.
The company intends to hold a public exhibition of its plans in the coming months to give residents and local groups the chance to have their say.
Plans are in the early stages, the company said, and it has not yet submitted an application to Stafford Borough Council.
Darren Humphreys, regional director of McCarthy and Stone, said: "We're keen to develop a scheme which positively contributes to the local community both through the high-quality, attractive design and the increase in local housing choice the development would bring to the area."
But the news has come as a blow to councillors who launched an energetic campaign to buy the land from British Waterways in 2009.
They hoped to turn the site into a community space and raised £100,000 towards the project.
This was achieved through a 50 per cent council tax hike – the equivalent of an extra £17 per band D household.
Councillor Jill Hood was involved in the council's Crown Wharf bid.
She said: "I am bitterly disappointed, but it is early days yet. I am hoping they are going to surprise us and it will perhaps be a development which has something for the whole community."
Property firm DTZ is handling the sale on behalf of British Waterways' successor, the Canal and River Trust. A DTZ spokesman told the Newsletter that the land would be sold subject to McCarthy and Stone obtaining planning permission.
Councillor Philip Jones, group leader for the town council's controlling Conservative party, said: "The first we heard at the town council was the land had been sold.
"We were not invited to make any offer or take part in any scheme.
"The site is currently rented by the town council from the Canal and River Trust for use as a free car park so this will be a loss."