It's not just unicorns that might be overvalued, ladies and gents. Now, more and more housing experts are coming out and affirming what some have been warning all along: we're in a bubble.

So say a third of housing experts surveyed by Zillow, reports the San Francisco Business Times, which goes on to note how the building consensus is especially alarming given the normal reluctance of most experts to make such declarative statements.

San Francisco was by far the big loser — or winner, if you recently sold your Bay Area home — in the quarterly survey that Zillow conducts with Pulsenomics. Of more than 100 panelists in Zillow's (NASDAQ: ZG), 66 responded to the questions about bubble conditions in 20 housing markets.

Other cities generating bubble talk in the Zillow survey were distant runner-ups: New York, Houston, Los Angeles, Seattle and San Diego. As usual, California is well represented on any list of possibly over-priced housing markets.

The Times further reports that an additional 20 percent of experts surveyed said the Bay Area housing market is "at risk of becoming a bubble within the next year."

As always, however, identifying a bubble is tricky business, and even those fancy experts don't always agree. And if even there is a bubble, it doesn't necessary mean a repeat of 2008.

"It's significant that some experts are starting to worry about bubble conditions, but in my opinion, there’s no real danger of a severe crash like the one we all remember from the last decade," the Times reports Zillow Chief Economist Svenja Gudell as saying.

Also, there's that hard reality that San Francisco has always been a pretty expensive place to live.

So, there you have it. We're probably in a bubble, but maybe not. Buy low, sell high, and stuff.

Related: Life After The Boom: What Will Happen When This Bubble Bursts