How Long Does It Take For A Site To Reach Authority Status?

Let's say you have a site with a domain that is semi-match and has your main keyword in it followed by something like a suffix or additional word (using a easily brandable domain). The site gets updated regularly with 100% unique content and uses only white-hat seo to prevent getting penalized. How long will it take for it to reach a point to where it can be named an authority site? 1 year, 2 years, 3 years ????

That depends on who do you want that Authority aims.
People that are looking for the subject are the ones to target. THEY will give you that status, and share your website, as an authority website on that matter. And that can take a loooong time... or not. Depends on how good you are with the content, and how good the competition is.

"Authority" isn't a measurable term because it means different things to different people. I consider an authority site one that will rank a low comp keyword with 10 minutes of posting content. I have a few sites that are crawled so frequently that my post will often rank on the first page before I can even refresh the search page. That's authority to me. The site has hundreds of real quality links and is about 7 years old.

"Authority site" has many different meanings. A loose definition would be a website you keep adding content to in one niche, and higher quality content. It has a high volume of traffic that are based on a multitude of keywords, instead of a central few. That seems to be the meaning many others use on BHW. I think an authority site is a hub of the niche. Not only does it receive backlinks, it receives them from the other most popular websites in its niche. For instance, seomoz could be considered an authority site because many other people in the SEO industry link to it. The same could be said of searchenginejournal, seobook, etc. Call your site "authority" whenever you think it is one. However, it may or may not fit other people's ideas of authority. In the end all that matters is how much money you make from it.

Consider "Authority" as PR (page rank)

Google will higher your PR when you get more relevant backlinks, at a steady pace (link velocity) and also as Google sees more social signals, your domains age also plays a factor (over 1 year is nice) and of course the more content you supply the better.

Broken even more simply, the more SEO you do the more authority your site will gain. It's not an over night thing.

When my posts landed on Lifehacker, or ars technica i said well i'm a tiny authority in the big Linux world. But it takes time, a year or two to get noticed