Emergency crews pumping water from a damaged dam above Whaley Bridge are close to reaching their target.
The Canal and River Trust has said it needs to drop the water levels by eight metres. Earlier the fire service said it was down 7.8m.
More than 1,500 people were evacuated from their homes on Thursday amid fears the 300-million-gallon Toddbrook Reservoir could flood the town.
They hope to find out later when they can return.
Authorities are expected to carry out more inspections ahead of a public meeting at 17:00 BST.
Fire crews have been using 23 high-volume pumps to remove the reservoir’s water since part of its spillway collapsed on Thursday following heavy rainfall.
The dam wall has been packed with 530 tonnes of aggregate, which is being cemented into place to reinforce the spillway.
Derbyshire Constabulary said: “Once a level has been reached – and is able to be maintained – engineers will view the damage to the wall and a decision will be made regarding when it is safe for evacuated residents and businesses to return to Whaley Bridge.”
Derbyshire’s Deputy Chief Fire Officer, Gavin Tomlinson, said they hoped to have “some good news” for residents later once water levels were down by 8m.
“That will allow the specialists to come in to assess the damage and they will provide the advice for somebody to make the decision with regards to the residents,” he said.
“Fingers crossed for them because they have been ever so patient, and hopefully we can give them some good news later. But we will have to wait and see.”
The fire service said it had used miles of pipes to remove the water and engineers had built two roads to allow the pumps to be moved closer to the site .
The Environment Agency is monitoring the River Goyt, where the water removed from the reservoir is being taken.
Police have criticised about 20 residents who stayed in their homes within the evacuation zone, saying they were “taking their lives into their own hands” and jeopardising the safety of the emergency services.
Deputy Chief Constable Rachel Swann said: “We will repeatedly visit these people to remind them of the risks they are posing to themselves and emergency responders, however there is no specific legislation under which we can force these people to leave.”
The Canal and River Trust, which owns the dam, said it carried out an annual inspection of the structure in November and it was “absolutely fine”.
The government has said it is considering a national review into the structural safety of dams across the country.