BEVERLY HILLS—Rent prices in Beverly Hills are falling noticeably as the city has been building a significant amount of new housing, and a chunk of that new inventory is sitting vacant. Within the past 12 months alone, Beverly Hills and Century City added approximately 400 new premium rental units, with close to 10 percent of them unoccupied.

Landlords are having to compete harder for a limited pool of qualified renters. Rent prices in cities like Palmdale, Lancaster, and San Bernardino are rising sharply. One-bedroom apartments in Palmdale have risen 12 percent year over year, with San Bernardino seeing a 5 percent increase, the New York Post reported.

Many residents have been priced out of these cities and are moving to more affordable neighborhoods. The shift is not only affecting hillside communities, but coastal ones as well.

Malibu saw a 3.6 percent decline, Huntington Beach fell 5.6 percent, and Redondo Beach dropped 6.9 percent year over year.

Data points to a genuine oversupply taking shape. Hundreds of new apartments and condominiums are under construction in Beverly Hills and are expected to hit the market within the next couple of years.

More units mean more competition among landlords for the same pool of renters, which will likely continue driving rent prices down.