"Some of the creeks in this system have just had incredible amounts of water through them."
He said the town's levee had held, but a voluntary evacuation order remained in force.
"There are lots of people who have moved back, including business owners," he said.
"They are assuming the risk that everything is in order - it appears that way - but that is not the official order.
Mr O'Brien said between 50 and 100 people remained at the evacuation centre at the Charleville Showgrounds.
"During the day there aren't too many there, but at night there are several hundred," he said.
"It's probably a sensible thing to do, but there is a risk by entering the evacuation area."
Mr O'Brien said the town's flood gates were just a week away from completion when the waters hit.
Charleville Motel owner Linda Edwards said residents would rest a little easier knowing the waters were slowly subsiding.
"The town's got an emergency siren, so we've been lying awake the past week just waiting for it to go off," she told AAP.
"I think we'll all sleep very well tonight."
Ms Edwards said her business had briefly been affected by the floods.
"We've got firies in and the Red Cross in, and government departments, so while you miss out on one hand, there's others to fill the gap," she said.
"The response time of those who are helping out has been fantastic."
