SAN DIEGO — Two cities in San Diego County are among the top U.S. metro areas with the lowest number of rental properties that are affordable with an average salary, according to a new study.

The study, conducted by personal finance website CashNetUSA, analyzed Zillow data from 200 cities across the nation to look at the number of properties that were available to rent for the traditional recommendation of 30% or less the area’s average income.

Over the last few decades, housing experts — including those with the U.S. Department of Housing and Urban Development — have used that percentage as the recommended amount of income that should be budgeted towards rent. However, finding a place using that metric has become increasingly more difficult.

For renters in San Diego and Chula Vista, struggles finding an affordable rental is an all-too-familiar experience, in part due to persistent housing shortages in the the metros that drives up price amid high competition for available units.

According to the study’s findings, the two cities were among the top 10 metros with the lowest share of rental units available for 30% the area’s average income — Chula Vista ranked No. 4, while San Diego came in at No. 10.

Roughly 10% of properties in Chula Vista were available for 30% or less the area’s average salary, according to the study. For San Diego, about 14.1% of rental units met the recommended budget.

For those spaces that are accessible for the average salary, residents in both cities are looking at properties with some of the least amount of space in the U.S.

In San Diego, the median income can afford a 523 square foot unit, according to the report — the fourth smallest property size out of the 200 metros analyzed. Chula Vista comes right behind in at No. 5 with the average income able to afford a 527 square foot property.

Another Southern California city, Santa Ana, came in as the place with the smallest available units — about 473 square feet — for a renter with the average salary.

For contrast, rental spaces in New York City, which is notorious for its tiny apartments, for the median income are about 774 square feet.

A full list of the top 20 cities with the smallest available affordable units can be found below:

  1. Santa Ana, CA – 473 square feet
  2. Honolulu, Hawaii – 491 square feet
  3. San Francisco, CA – 514 square feet
  4. San Diego, CA – 523 square feet
  5. Chula Vista, CA – 527 square feet
  6. Boston, MA – 534 square feet
  7. Seattle, WA – 553 square feet
  8. Oakland, CA – 573 square feet
  9. Missoula, MT – 585 square feet
  10. Long Beach, CA – 589 square feet
  11. Cambridge, MA – 602 square feet
  12. Los Angeles, CA – 612 square feet
  13. Stamford, CT – 613 square feet
  14. San Jose, CA – 637 square feet
  15. Riverside, CA – 638 square feet
  16. Denver, CO – 648 square feet
  17. Irving, TX – 652 square feet
  18. Anaheim, CA – 655 square feet
  19. Yonkers, NY – 657 square feet
  20. Arlington, VA – 669 square feet

Nationwide, the average household has reported paying more than 30% for their home for the first time in 25 years, according to a recent report from real estate data firm Moody’s Analytics.

This trend is driven by a couple of coinciding factors, experts say, including rising mortgage rates that are pricing would-be home buyers out and a limited supply of rental units to meet demand.

According to the CashNetUSA study, Miami was the market with the least affordable options when it comes to renting, with just 7.8% of units available for 30% or less of an average salary. Profound wealth inequality in Miami has exacerbated this shortage, experts say.

A full list of the top 20 cities with the fewest affordable properties can be found below, including its market share represented as a percentage:

  1. Miami, FL – 7.77%
  2. Cambridge, MA – 9.18%
  3. Boston, MA – 9.33%
  4. Chula Vista, CA – 10%
  5. Gilbert, AZ – 10.71%
  6. North Las Vegas, NV – 11.39%
  7. New York, NY – 11.63%
  8. Santa Ana, CA – 12.87%
  9. Savannah, GA – 14%
  10. San Diego, CA – 14.1%
  11. Scottsdale, AZ – 15.23%
  12. Henderson, NV – 15.73%
  13. Meridian, ID – 17.03%
  14. Chandler, AZ – 17.18%
  15. Frisco, TX – 18.93%
  16. Bellevue, WA – 20.81%
  17. Virginia Beach, VA – 21.41%
  18. Plano, TX – 24.06%
  19. Tampa, FL – 24.69%
  20. Riverside, CA – 25%