According to the state Department of Finance, California had 532,000 more residents at the end of 2003 than it had at the beginning.

Ho hum. This has been going on for quite a while in California – and not just for a decade or two or three. Ever since the Great Depression gave way to World War II 63 years ago, California has been adding about a half-million people a year to its population. During that time, the state’s population has grown from around 6 million people to going on 40 million. And there is no reason to expect that to change anytime soon.

What is changing is where and how people live. In some parts of the state, we are seeing a return to old suburban patterns. Yet in other ways, we are seeing a continuing transformation of California into an urban society. As usual, here in California we are doing everything at once.

Perhaps the most startling change is what’s going on in the Bay Area. Population growth in the Bay Area has all but stopped, at least for the moment. The nine-county bay region actually saw a small decline in population last year, and since 2000 population growth in the region has been less than half the statewide average (3.3% as opposed to 6.7%). There’s a little suburban-style growth in places like Contra Costa and Sonoma counties, but elsewhere around the bay population is decreasing.

Meanwhile, the population in Southern California is increasing a great deal, especially in suburban areas like Riverside County. Los Angeles County continues to be a population machine, adding almost 600,000 people since the 2000 Census, but Los Angeles County is growing at about the state average. The real story is in Riverside, which has added almost 230,000 people since the census, an increase of 15%. Riverside County has now passed Santa Clara County as the fifth most populous county in the state. Soon it will pass San Bernardino to become number four, behind L.A., Orange, and San Diego counties.

The most interesting part of the population story in Southern California is the contrast between Riverside and Orange. In the ‘90s, Orange County grew faster than the statewide average and, at least in raw numbers, added more people than Riverside. But no more. Since 2000, Orange County has added 170,000 persons (a 6% increase) -- but that pales in comparison to Riverside County’s growth.

So, what’s happening? Have we entered a re-suburban era? Are young families chasing new single-family houses deep into the desert and the Central Valley in order to get a piece of the American dream? Well, yes and no.

According to the state Department of Finance estimates, the overwhelming majority of housing units that have been built in California since 2000 — 74% — are single-family homes. That’s about the same as during the 1990s. The difference in recent years is where these homes are being built, and what the other 26% consists of.

Single-family homes are being built in large numbers in Riverside County and the Inland Empire, and at a more frantic pace than we saw during the 1990s. In the coastal areas, where average prices hover around the half-million-dollar mark, the modest trend of the ‘90s towards townhouses has been replaced with a movement toward multi-family condos and apartment buildings.

First to the single-family home construction. There is no question that housing production is shifting back to the inland areas in a way that was not true during the ‘90s. The urban coastal areas – San Diego, Orange, and L.A. counties and the Bay Area combined – have accounted for only 44% of the state’s total housing production since 2000. Meanwhile, in the blazing Riverside County market, single-family detached homes have accounted for almost 90% of housing starts in the last four years – up from 81% during the ‘90s. In fact, from 2000 through 2003, Riverside County produced 66,000 single-family homes – twice as many as any other county. In metro Sacramento, the single-family detached figure for the last four years is 85%. In San Joaquin County, the leading “Bay Area spillover” county, the single-family detached figure from 2000 through 2003 was almost 98%.

In the coastal areas, things look very different. Townhouses have dropped from 12% of new housing units to only 1%. But multi-family units – apartments and condo projects with five units or more – have gone in the opposite direction, increasing from 7% of all housing production to 22%.

In some coastal counties, multi-family construction now exceeds single-family construction, and it comes close elsewhere. From 2000 through 2003, multi-family construction exceeded single-family construction in four urban coastal counties – San Francisco, Santa Clara, San Mateo, and Los Angeles – and came close in Alameda County. In L.A. County, multifamily projects have increased from 10% of new housing during the ‘90s to 50% during the ‘00s. In Santa Clara County, the multi-family figure rose from 26% to 62% of all new housing production.

In the other two big urban coastal counties – Orange and San Diego – single-family construction still outstripped multi-family construction, but the numbers are very different than they were in the ‘90s. In Orange County, the multi-family figure rose from 13% to 32%; in San Diego, it went from 11% to 30%.

As we have seen in the past, California is bifurcated in many ways – not just north-south, but east-west as well. The new Department of Finance figures suggest that both of these splits are alive and well. In the north-versus-south, the Bay Area has stopped growing, while coastal Southern California is still adding lots of people.

But this north-south split may not be as important as the east-west split because the east-west split is not about how many people there are, but about how they live. In interior California, people build and buy single-family homes in overwhelming numbers. But in the coastal areas, residential trends are changing. And the change is not from single-family homes to townhomes – a modest shift. The adjustment is from single-family homes to condos and apartments – a big shift, and one that is sure to alter the politics of growth in California in the years ahead.