Rental affordability also hits four-year low.

Concessions are at a record high as rental affordability reached levels not seen in years. According to Zillow, 37.3% of rentals have concessions, which is a record for the month of September. The previous monthly mark was 14.4% in September 2019. It's expected that concessions will top off in the winter or early spring.

Austin, Texas (-4.7%), Denver (-3.4%), San Antonio (-2.3%) and Phoenix (-2.2%) witnessed some of the largest rent declines during the past year. Some of the metros with the highest share of rentals with concessions included Denver (64.8%), Charlotte, N.C. (62.7%), Austin (60.4%), Dallas (58.9%) and Atlanta (55.9%).

Nationally, the rent index sits at $1,979, or 28.4% of a median family's income, which is down from 28.8% a year ago.