Houston's flooding disaster is pushing the limits of its emergency call services. As Tropical Storm Harvey dumped historic amounts of rain, 911 operators in Houston processed 75,000 calls between Friday night and Monday morning. Normally, the city gets 8,000 to 9,000 calls per day and many people who need help have complained about their calls going unanswered.

But while 75,000 calls have been received and processed since Harvey first hit, that number doesn't include the thousands of other calls that never make it to the front of the call line. Officials say when people call and hang up without waiting to speak to someone who can help, it creates a backlog. That could mean it takes a lot longer for police and fire crews to make much-needed rescues, reports CBS News correspondent Jericka Duncan.

"We're advising people to go ahead and stay on the line," said Joe Laud, the administration manager at the Houston Emergency Center.

Asked how quickly police are getting dispatched to people who are stranded, Laud said, "We prepare that information for dispatch purposes, and of course we can't speak for police and fire response, because they're tied up with so many emergencies as well," Laud said.

Laud says the 911 problem is complicated when people hang up and try calling back.

"The worst thing they can do is hang up because what ends up happening is, it's almost – they're back at the end of the line," Laud said.

More than 200 people have been working 12-hour shifts since Saturday; normally just 25 people are answering those phones.

For operator Katherine Tyler, who lost her car and her home, the work has become personal.

"I love this job. I've been doing this job for about four and a half years. They need help, my co-workers, they're working long hours, I needed to get here and help them," Tyler said.

The emergency center also has a voice-activated system telling people their calls are being processed, but some of these cases just can't wait. There have been a number of calls involving women in labor so call-takers have had to literally talk people through home deliveries.

2 Wants to Know reached out to Triad 911 Centers to see how they would handle an emergency situation.

The state mandated all of them to have a backup plan incase their lines go down.

Guilford County said it would use its old location on Meadowood Drive. The county agreed to share its backup center with high Point and Rockingham County.

Forsyth County told us if it had to evacuate the building, the calls would roll over to the Forsyth County Sheriff's Department then to Winston-Salem police.

That means, in an emergency, you call will be answered.

Herb Swain, the 911 systems manager for Forsyth County, said they average about 250 calls a day, but there have been cases when they've had that many calls in one hour.

"If we were to get in a sutation where our 911 systems became overloaded, they would not be abandoned," Swain said.

He added that there are roll over plans to make sure those calls are eventually answered.