Thunderstorms are threatening to bring more unwanted rainfall to a Derbyshire town where a damaged dam is thought to be at risk of collapse.

Whaley Bridge remained eerily quiet on Sunday morning as residents anxiously waited, with forecasters predicting days of heavy rain.

A team searching for missing pets in Whaley Bridge. Photograph: Rod Kirkpatrick/The Guardian

Meanwhile, those who were evacuated from their homes were told on Sunday they would no longer be able to return to collect vital items. More than 1,500 residents were initially told by emergency services they would be allowed to briefly return home on Sunday to collect any necessary items, pets and medication they had left behind.

But the weather forecast forced police to reverse the decision amid heightened safety concerns over the damaged dam at Toddbrook reservoir.

After a command team meeting on Sunday morning, Derbyshire police said its decision was taken due to emergency service workers prioritising the “preservation of life”.

The force added: “While there was an urgent need over the past 24 hours to allow residents back into the area, our first duty is to protect the lives of the public and emergency services.”

Hazel Thompson, who grew up in the town, said residents were waiting to see what would happen with the weather.

Emergency teams continue to repair Toddbrook reservoir near Whaley Bridge. Photograph: Peter Byrne/PA Media

“We have been told that they have now stopped dropping the aggregate and they are just working hard to lower the water levels even more,” Thompson said.

She added: “Some roads have now been completely closed off and if residents leave their homes they are no longer being allowed to go back in.”

Gavin Tomlinson, Derbyshire’s deputy chief fire officer, said teams at Whaley Bridge had made good progress overnight.

“We now know we have taken around 35% of the contents of reservoir out now and we are aiming to get it down about 25% where we think it is at a safe level,” he said. “So throughout the night what we have done is concentrated our efforts on making sure all the pumps run to full capacity.

“That means as the water level drops – the reservoir doesn’t have straight sides, it comes in [with sloping sides] – so we have to keep relocating the pumps further and further in.”

Just over six miles away in the town of Marple, on the outskirts of Stockport, the army has been deployed amid fears the River Goyt could overflow. Water from the Toddbrook reservoir is being released into local waterways, which is leading to an increased risk of flooding in nearby areas.

Police officers talk to residents during the 15-minute window when people were allowed to return to their homes. Photograph: Leon Neal/Getty Images

Greater Manchester police said there was the potential for the situation at the reservoir to affect Marple, but stressed there were no plans to evacuate the town and said advice was being given out as a precaution.

The Canal and River Trust estimated on Saturday that 105,000 cubic metres (23m gallons) of water had been pumped out in 12 hours with water levels being reduced by 1.3 metres since Thursday, but the condition of the structure remained critical.

An RAF Chinook helicopter put 400 tonnes of sandbags on the affected part of the dam on Friday and added a further 70 on Saturday.

Daniel Greenhalgh, a regional director at the trust, which owns the reservoir and dam, said: “We are not out of the woods yet. The last estimate was that residents could be out of their homes for seven days yet.”

Sandbags being delivered outside shops in Whaley Bridge high street. Photograph: Vickie Flores/EPA

The trust has defended the maintenance and safety of the 188-year-old structure.

Greenhalgh said: “This dam was inspected regularly by us and an independent engineer. It needs to be remembered there was a huge amount of rain in a short time and this flooded the area.”

A further 55 homes in the Horwich End area of the town were cleared on Saturday evening, two days after 1,500 residents left.

Derbyshire police allowed one person from each of the 400 properties evacuated on Thursday to return for a 15-minute visit on Saturday to pick up pets and other essentials.