SAN RAFAEL (CBS SF) — The median price for a Marin County home is nudging up against the million-dollar mark.

The Marin County Assessor’s Office says the new median price of a home in that county is now $999,000, a 13-percent jump from just one year ago.

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Tight supply and rising demand are likely behind the surge.

“We have over 80-percent of the county that can’t be built on, where it’s protected seashore, state park, open space, water district, you name it,” Matt Hughes of the Marin Association of Realtors said.

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Hughes says the competition is steep for buyers, with many homes going well above the asking prices.

“Investors know that they can step into that house, put the money into it, and get a higher return when they choose to go on the market.”

Hughes expects more homes to hit the Marin County market in the spring.

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“A lot of people have been waiting through those tough years.  They may have wanted to sell four to five years ago and then changed their priorities or changed their plans because they couldn’t walk away with their equity.  They had lost that equity.  Equity has returned and now they can leave money in hand.”