Splashback submitted a plan to buy the hugely popular attraction for a token sum of £1 and run the swimming centre instead of Edinburgh Leisure.
But officials have recommended that the bid be turned down, with the council instead seeking to put the site on the open market next year.
Campaigners said the news was “frustrating”, while local councillors vowed to keep up the fight to save the community facility.
Edinburgh Leisure had been operating the site at a significant loss in recent years –£340,000 in 2011 – and the community group said it could reduce this by extending opening hours and cutting the wage bill.
However, the group would have needed leisure chiefs to hand over £740,000 over the next three years to plug losses. And it would have cost £155,000 to get Leith Waterworld up and running again, negating the narrow savings Splashback had promised.
Edinburgh City Council, which owns Edinburgh Leisure, will make a decision next week but officials have already recommended seeking a private buyer instead, which the administration is expected to back.
Property advisor GVA, which was commissioned by the council to assess the bid, said in its review: “Splashback’s contribution appears only to be as an operator with the aim of improving visitor numbers through increased tariffs and reduced staff costs. There is very little evidence of how this can be achieved.“
But Splashback, run by local families and community activists, slammed the report, which was also attacked by councillors.
Campaigner Johnny Gailey said: “I just think it’s all a bit jaundiced – it’s frustrating [the council] have had to get an external consultancy in to write a report that they can potentially hide behind.
“The new administration said there had been a breakdown in trust between the council and the people, and that it wanted to do things differently. What we are proposing is different and what the report recommends is just the same old.”
Edinburgh Leisure and Edinburgh City Council had valued Leith Waterworld at £1.5 million – earmarked for the Commonwealth Pool project – and officials said Splashback’s offer of £1 would have resulted in a significant shortfall.
Taxpayers would also have to fund a £2.2m refurbishment over the next ten years, which a private firm would pay for if it bought the site.
Councillor Chas Booth, Green member for Leith, said: “The Labour-SNP administration has said it wants to transform the relationship between residents and the council, putting more power in the hands of local people.
“So, for the council, it is a test of words into action and an opportunity to maintain and enhance a unique asset.”
Councillor Gordon Munro, Labour member for Leith, said: “I am disappointed at [the recommendation] and I will be arguing counter to it at our group meeting on Tuesday night.
“With the entrenched community support that’s already there, something special could happen here.”
Richard Lewis, the city’s culture and leisure leader, said: “I want to acknowledge the effort that Splashback have put into this and their bids merit careful consideration.
“I have already said that I would be delighted if there was an affordable and achievable community bid, but we will all need to consider the report about the two offers from Splashback before reaching a decision.”