On Friday, the San Diego County Registrar of Voters dropped off its first batch of outbound mail-in ballots at the post office.

Chances are good you'll find a ballot in your mailbox next week, but how can you be sure it gets to the right place when you send it back? 

For the vast majority of voters in San Diego County, finding a ballot in their mailbox is nothing new.

“San Diego voters have been used to voting by mail,” said Michael Vu, the San Diego Country Registrar of Voters. “Their preferred method is voting by mail.” 

In fact, 78 percent of San Diego County voters are already permanent mail-in voters. What is new is a way to track your ballot through the entire mailing process – it’s a lot like how you track a package through FedEx or UPS.

“We’ve always provided voters A to Z,” Vu said. “Now voters have the ability to see B through Y.”

It's free, easy and I did it in less than 5 minutes. Here's how:

• Go to SDVote.com
• Scroll down and click on "Where's My Ballot?"
• A page of instructions will load, then a link to sign up will appear
• Hit that link, and a prompt to enter some basic info appears: name, birth date, ZIP code
• Next. select how to get push notifications: e-mail, text or phone call

I picked text notifications between 8 a.m. and 8 p.m. I got a text asking me to reply “Yes” to confirm, and that's it! I can now track my vote. Apparently I’m in good company.

Vu said that 130,000 San Diegans already signed up to track their votes. Not bad, but there are 1.9 million registered voters in the county.

“I think it’s a great addition, and I’m really glad it’s available for voters statewide,” said Kim Alexander, who is with the nonpartisan California Voter Foundation.

The nonprofit studied rejected mail-in ballots statewide over the last 10 years. It determined that the No. 1 reason ballots got rejected wasn't because they got lost in the mail -- it was because they were postmarked too late in order to be counted, meaning that those ballots weren’t postmarked by election day. In fact, Alexander said the vast majority of late mailed ballots in Sacramento were postmarked the day after election day – meaning these folks likely dropped off their ballots on Election Day after the post office closed.

This is why, despite the new tracking tool, Alexander said the best way to return a ballot is in person at a drop-off site, county election office or voting site.

“Not all voters understand that just because it’s called a vote-by-mail ballot means you have to return it by mail,” Alexander said.

Another reason mail-in ballots get rejected is because the signature on the ballot envelope doesn't match the signature on file. A good way to check yours is to take a look at your driver’s license. That's likely the signature the elections office uses as a reference point.

“The fact is, voting by mail shifts the responsibility for getting it right when you cast a ballot from the poll worker to the voter,” Alexander said.

That California Voter Foundation study found on average 1.7 percent of mail-in ballots get rejected statewide every election. That might not sound like much, but in a state of 21 million registered voters, it amounts to tens of thousands of uncounted votes.