SAN FRANCISCO (CBS SF) — A San Francisco Supervisor wants to tax out-of-town property owners who let their units sit vacant.

As people desperately search for housing, a new study reports that there are about 18,000 properties off the market, and half of those are second homes for people who live elsewhere.

READ MORE: Oakland Fire Crews Battle Two-Alarm Blaze At Apartment Building

“Some call them zombie neighborhoods when you have out of town people that own them, but don’t live in them,” Mar told KPIX 5.

Mar is working on a plan to tax some of those properties.  He wants to put a measure on the ballot in November, but says he will have to iron out the legal issues with the city attorney.

READ MORE: FBI: Apparent Human Remains Found Near Brian Laundrie's Belongings

“A tax on people who don’t even live in San Francisco who own these luxury condos would be a disincentive for people hoarding these multimillion dollar condos and hopefully allow others to purchase and live in them,” Mar said.

Dan Hendel, a realtor, says he has clients who don’t want to rent out their extra property because they may want to sell it later.  Some simply don’t want renters because they, or a family member may eventually move in.”

Hendel says the city shouldn’t have a say over what property owners do with their homes.

MORE NEWS: COVID: FDA Authorizes Moderna, Johnson & Johnson Booster Shots

“If they have an extra property in the city that they only use occasionally, they should be able to use it any way they want.”