Investigations are underway at two former landfill sites in Lincoln to see whether the land could be built on.
The work on the Skewbridge and Swanpool waste sites is part of wider project work on the Western Growth Corridor.
The £250 million development would provide up to 3,000 homes along with increased employment, green spaces and improved infrastructure.
Work started on Monday, June 2 and is expected to last for about two weeks, followed by some ongoing monitoring work over a six month period.
The investigation will be carried out by environmental consultants WSP, who will assess the site for contamination and the geo-technical properties of the soil including its strength and stability.
An ecology survey should also help with the identification of possible remediation options for the waste sites.
WSP will then be able to advise the council on possible uses for the site and the work which may be required to bring the ground back into use.
Besides being a former waste site, the area is also prone to flooding.
City of Lincoln Council Leader Ric Metcalfe said: “This is essential exploratory work looking at the condition of these former landfill sites. When we know what the options are we can consider the best way forward to help us achieve our aims.
“Growth is essential to ensure Lincoln’s future, and the Western Growth Corridor is the biggest and most sustainable site we have to enable us to provide homes, jobs and services for a growing population.
“Any development would need to be safe and appropriate, which is why we are carrying out this investigative work.”