Properties in Hopkins Street at Speers Point were among those to be hit by flooding on Sunday.
"Water has gone through some of the houses and wrecked a lot of yards," resident Philip Uebergang said.
He said mud and water had "come down the street thigh-deep".
The flooding was at its worst at about 6.30am on Sunday.
"These photos were taken after the floodwater had receded," Mr Uebergang said.
"The water is entering the street through a neighbour's property. His power pole and services have all been undermined and exposed."
Meanwhile, Ausgrid said 77,000 customers were without power across Newcastle, Central Coast and Sydney on Sunday night.
"Crews will work through the night to get the power back on. Thank you for being patient in these trying conditions," a statement said.
Charlestown, Kotara, New Lambton and surrounding suburbs lost power for several hours on Sunday, but it was later restored. Cams Wharf, Catherine Hill Bay and Caves Beach were also affected.
At 12.30pm on Sunday, train services were suspended between Gosford and Morisset in both directions due to external power supply issues affecting signalling and track equipment at Wyong. Bus companies were called in to run replacement services.