Thousands of people were affected. Sonoma county officials are asking AT&T how such a thing could happen.
Cloverdale, Geyerserville and parts of Healdsburg were affected.
The big concern was public safety because people couldn't pick up their phone and call 911. That is why police had an officer stationed at two gas stations in Cloverdale, because they are both open 24 hours a day.
They wanted to keep the businesses safe and make sure that no one took advantage of the situation. They also wanted people to see the officers in case they needed them.
Everyone in town was relieved when their phones started working at 8:30 a.m. on Wednesday morning.
Loosing phone service can be bad for businesses, as the wait staff at the Star Café found out when the credit card machine wouldn't work because the line was dead.
"I had to turn away some people this morning because they have to pay with a credit card. So they weren't able to eat this morning," said Star Café waitress Patsy Buchignani.
But emergency officials were more concerned this morning on what would happen if someone chocked on their breakfast, since the people of Cloverdale, Geyserville and parts of Healdsburg wouldn't be able to pick up their phones and dial 911.
The police department posted fliers with the phone numbers people should call from their cell phones in case of an emergency.
"They all have our cell phones, it didn't impact the cell phones like it did the regular lines service," said Buchignani.
But cell phones don't always work in scenic Sonoma County.
"It's frustrating, because sometimes your cell phone doesn't really work either up here because of where we are at, and because of the hills," said Willi Castagnetto of Cloverdale.
This made it tough for loved one to stay in touch. Her husband is out of town on a business trip and he spent four hours trying to call her.
"He was really upset, he thought something was really wrong because they couldn't get through," said Castagnetto.
But the Cloverdale Police Chief said luckily it was a quiet night. His department didn't receive a single phone call overnight on the lines set up to handle 911 calls.
"Hopefully there were no emergencies, we'll find out later today," said Cloverdale Chief of Police Mark Tuma.
He did put all of his officers on 12-hour shifts, so they could watch for the vulnerable city, and be visible for anyone who needed them.
He was even ready to bring cell phones for those who don't have one.
Overall, he called this a good test, and hopes people come up with some back up plans.
"It would be nice for a neighbor to call their other neighbors and say 'hey here's a cell phone if you need to call.' That would be nice to have neighbors like that," said Chief Tuma.
So what happened? AT&T said it immediately got crews out and down into the manhole assuming that maybe a line had broken.
They say that's a logical assumption, but they couldn't find where the line was broken until they figured out that there was a power outage at their main center in Geyserville.
Now they are trying to figure out why that power outage happened.