The construction of a luxury spa hotel on historic Buxton Crescent will not begin before October, developers say.
The £35m project has been hit with a series of delays because of the derelict building's site over the source of the famous Buxton spring.
An archaeological dig will finish this week and drilling to uncover the exact location of the spring, which supplies bottled Buxton Water, has been ongoing.
A spokesman for the development said it was hoped work would start in October.
Jonathan Ogden, from Danubius, the hotel group which will operate the restored site, said: "We are dealing with an extremely important and fragile site.
"We have to go step by step, we simply can't afford to rush something."
Developer Trevor Osborne said his company had a duty to preserve such an historic site, which has been empty for 15 years.
He said: "We've got a lot of history here. This is a site which we know was a Roman spa.
"Buxton Water is an important business in the town and its owners Nestle wanted to protect that and make sure that nothing could happen on the site that would interfere with the flow and quality of the water."
He added: "We couldn't plan for delays like these. Nobody could have foreseen the complex legal nature of the negotiations that had to take place."
The earliest possible date for completion of the luxury spa hotel is 2012.