Southern California’s home sellers are witnessing the slowest market for existing home sales in 20 months as competition for buyers is up and demand falls, a new report shows.

ReportsOnHousing tracks homebuying patterns found in real estate broker networks: supply (active listings); year-to-date increase in supply; demand (new escrows in past 30 days); and “market time” (a measure of selling speed of days it takes a typical listing to enter escrow). This data does not track builders’ newly constructed homes — and that niche has growing supply, too.

As of Sept. 6, market time in the four-county region covered by the Southern California News Group hit 92 days vs. 67 a year earlier and an average 80 days in 2012-2017. Yes, 25 extra days for a home to go from hitting the market to a signed sales contract and into escrow. The last time the market for existing homes was slower was January 2017.

With this metric surpassing 90 days, by ReportsOnHousing’s logic, selling conditions are no longer a “seller’s market,” rather a more “normal” balance between supply and demand. Numerous theories have been suggested to explain the slower pace.

Mortgage rates are rising, upping the size of the monthly house payment for prospective buyers. That has yet to lower pricing, putting further strain on wannabe owners’ household budgets. The increased supply may lower the house hunter’s urge to act quickly. (And, by the way, the sales pace at local car dealers have slowed, too.)

How did house hunting for existing homes in Los Angeles, Orange, Riverside and San Bernardino get to this juncture?

Supply is way up: 36,098 listings, up 5,822 residences in a year or 19 percent; and up 8 percent vs. the six-year average. And demand is way down: 11,717 new escrows, down 1,853 sales contracts in 12 months or 14 percent; and down 12 percent vs. the previous six years.

“We thought we would need to see a lot more listings to pull this market out of the seller’s hands, but instead it really boils down to a tremendous drop in demand,” says ReportsOnHousing author Steve Thomas. “Buyers are not buying because home values are high and any bump in interest rates hurts the family budget. A 7 percent increase in home values and rates moving from 4 percent to 4.66 percent crushes the typical family. (Prices) going from $700,000 at 4 percent to $750,000 at 4.66 percent costs an additional $5,000 per year. Ouch!”

It’s the same story the the county level. Let’s start with Los Angeles County …

Supply: 14,166 listings, up 2,317 residences for sale in a year or 20 percent; and up 5.9 percent vs. 6-year average.

Demand: 5,027 new escrows, down 881 sales contracts in 12 months or 15 percent; and down 13 percent vs. previous six years.

Market time: 85 days vs. 60 a year earlier and an average 74 days in 2012-2017.

In Orange County …

Supply: 7,070 listings, up 1,431 residences for sale in a year or 25 percent; and up 11 percent vs. 6-year average.

Demand: 2,162 new escrows, down 462 sales contracts in 12 months or 18 percent; and down 20 percent vs. previous six years.

Market time: 98 days vs. 64 a year earlier and an average 76 days in 2012-2017.

In Riverside County …

Supply: 8,932 listings, up 1,314 residences for sale in a year or 17 percent; and up 6 percent vs. 6-year average.

Demand: 2,530 new escrows, down 266 sales contracts in 12 months or 10 percent; and down 9 percent vs. previous six years.

Market time: 106 days vs. 82 a year earlier and an average 95 days in 2012-2017.

In San Bernardino County …

Supply: 5,930 listings, up 760 residences for sale in a year or 15 percent; and up 11 percent vs. 6-year average.

Demand: 1,998 new escrows, down 244 sales contracts in 12 months or 11 percent; and down 1 percent vs. previous six years.

Market time: 89 days vs. 69 a year earlier and an average 85 days in 2012-2017.

Please note that local builders 3,336 completed homes for sale in Los Angeles, Orange, Riverside and San Bernardino in the second quarter, according to MetroStudy. That’s up 19 percent in a year and the highest standing inventory since the early days of the economic recovery in 2012’s second quarter.