Average rents in San Diego County have fallen for six straight months and have reached a milestone not seen since in 15 years.

Rents are down 0.3% year-over-year to an average $2,520 per month in early December, said real estate tracker CoStar. San Diego County has not seen average rent decline on an annual basis since the end of 2010.

The biggest drops have been in the expensive areas, like downtown San Diego, while rents have increased in National City and Escondido.

One of the drivers of the rent slowdown is a 5.7% vacancy rate, its highest since 2009. That’s a monumental change in just a few years. In 2021, the vacancy rate fell to 2.64%, the statistical equivalent of someone moving out and a new renter moving in a few days later.

Joshua Ohl, senior director of market analytics for CoStar, said there are a variety of factors driving down rents: Several years of record-breaking apartment construction, local wages not keeping up with housing costs, and a comedown after explosive rent growth.

He said the annual rent growth in San Diego County shot up to 11.3% in 2021, compared to about a 3% annual average over the last 25 years.

“We had annual rent growth (in the pandemic) in the double digits,” he said. “We essentially had about four years of rent increases in one 12-month period.”

Rental data is a bit of a preview of the economy as most other reports — inflation, unemployment and others — have been delayed because of the recent government shutdown. CoStar has the largest local database with nearly 300,000 apartments and much of it is up-to-the-moment because large landlords often upload prices directly.

Lucinda Lilly, an apartment specialist who consults for several property management firms in San Diego County, said she is in the trenches now with many renters asking for concessions, or rent reductions, to stay in units. She advises landlords to offer concessions because it is still cheaper than leaving an apartment empty for a few months.

The decline in rental prices isn’t just in San Diego County. National rents were down 2.2% annually in November, said real estate website Zumper, which tracks rents by one-bedroom units. New York had the most expensive rent in the nation at $4,330 a month for a one-bedroom. San Diego was in eighth place at $2,250 a month.

CoStar breaks down rents by submarkets to get bigger statistical areas. Some markets might raise eyebrows, like Balboa Park, because it has some of the oldest apartments in the county, which is why its rents — on average — are lower. Here’s how rent breaks down by area, ranked by rent reductions:

Downtown San Diego - Average monthly rate: $2,087, down 1.4% in a year. Vacancy rate: 9.8%

South I-15 Corridor (Sorrento Valley, Miramar, Mira Mesa). Average monthly rate: $2,986, down 1.2% in a year. Vacancy rate: 4.5%

Central Coast (Pacific Beach, Mission Beach, Ocean Beach, Point Loma, Coronado). Average monthly rate: $2,402, down 1% in a year. Vacancy rate: 4.9%

North Shore Cities (Del Mar, Encinitas, Solana Beach). Average monthly rate: $3,462, down 0.9% in a year. Vacancy rate: 3.8%

Mission Valley/North Central (Clairemont, Kearny Mesa, Allied Gardens). Average monthly rate: $2,849, down 0.7% in a year. Vacancy rate: 6.8%

Balboa Park (North Park, University Heights, Hillcrest, South Park). Average monthly rate: $2,087, down 0.4% in a year. Vacancy rate: 7.3%

Chula Vista/Imperial Beach - Average monthly rate: $2,442, down 0.4% in a year. Vacancy rate: 6.5%

La Jolla/UTC - Average monthly rate: $3,239, down 0.4% in a year. Vacancy rate: 3.7%

Outlying San Diego County (Julian, Campo, Jacumba Hot Springs, Alpine). Average monthly rate: $2,078, down 0.2% in a year. Vacancy rate: 6.1%

East County (La Mesa, El Cajon, Grossmont, Rolando Village, Talmadge, College Area). Average monthly rate: $1,996, unchanged annually. Vacancy rate: 5.3%

North County (Oceanside, Carlsbad, Vista). Average monthly rate: $2,519, up 0.3% in a year. Vacancy rate: 4.4%

Poway/Santee/Ramona - Average monthly rate: $2,222, up 0.4% in a year. Vacancy rate: 5%

National City/South Central - Average monthly rate: $1,940, up 0.6% in a year. Vacancy rate: 4.2%

North I-15 Corridor (Escondido, San Marcos). Average monthly rate: $2,496, up 1.5% in a year. Vacancy rate: 5.2%

Source: SDuniontribune by Phillip Molnar