"Real Housewives of Beverly Hills" star ADRIENNE MALOOF had barely settled into her new home before she was forced to pack her bags and leave – because she says it's FILLED with toxic mold!

The 51-year-old Bravo star leased the 10,000- square-foot mansion in the posh-gated Mulholland estates community in Beverly Hills in November after moving out of the home she'd shared with ex-hubby/plastic surgeon DR. PAUL NASSIF.

The palatial three-story rental, which boasted a library and a theater, cost a whopping $20,000 a month, with an option to purchase for $6.5 million, according to published reports.

But now Adrienne is staying at a plush hotel bungalow with her three sons – Gavin, 9, and 6-year-old twins Collin and Christian – until she finds another place to live.

"A couple of weeks ago, Adrienne's boys were downstairs in the media room getting ready to watch a movie when they noticed their shoes were wet," a family friend told The ENQUIRER.

"They thought it might be a leak somewhere, so they mentioned it to their mother. Adrienne took one look, saw black mold growing around the area and knew that they had to get out of there right away. "She freaked out and told the kids to grab an overnight bag and hurry up!"

They took off on a family skiing trip while Adrienne — who recently split from ROD STEWART's troubled 32-year-old son SEAN — planned her next move. Fortunately, she was able to break her lease.

Mold in the home can cause health problems ranging from itching eyes, sneezing and coughing to serious allergic reactions, asthma attacks and even permanent lung damage.

"Luckily, Adrienne had decided to only rent the mansion for a year to see if she liked it enough to buy it," added the source.

"Needless to say she's now decided to give it a pass."