People in spring-green Southern California still are buying new and resale houses at Washington level prices, but you can detect signs - and get opinions from realty professionals - that there's a slow leak in the housing market bubble.

Southlanders, as they call themselves, still are buying homes in a growing area facing state and local restrictions on construction. But they are finding themselves increasingly under pressed to meet rising monthly payments as mortages rates near 10 percent.

Because so many home owners have been taking advantage of the equity in their own homes to sell and move to $100,000-plus new houses, there now is widespread concern about the willingness of enough first-time buyers to [WORD ILLEGIBLE] the lower range of resale houses.

Everyone in real estate - whether it be in Southern California or Washington, D.C., or Kansas City - realizes that the upper-priced housing market cools - when nobody comes along to buy the lesser houses being vacated.

With so many of the new homes in Grange County and neighbouring San Diego County to the south now priced above $100,000, even the confidence that residential real estate is today's most possible investment is being resulted this spring.

Home sales in San Diego County fell to 7 percent in the first quarter of this year to produce what Building Research Consultants Inc. calls "an unstable climate" for the first time in two years.

Nonetheless, the number of deeds recorded and real estate loans made in the Diego County set a record in March, when sales spurted. However, the forecast for the rest of the year is for moderately lower sales and an increase in house inventories if inflation continues high and borrowed money become both scare and high-priced. It's already costly to get loans, but funds are available.

Anyone making a move to California's lower Sunbelt soon discovers a price structure that can deter middle-income families or retirees without a sizeable nest egg to invest. Prices for new houses start mostly at $50 a square foot and move quickly over the $100 level for plush condominiums and singles with even a remote ocean or mountain view. Thus, it's easy to find new houses priced at $150,000 to $250,000. The premium for what is called a "view house" is often $40,000.

One relatively recent arrival, the executive manager of a Sheraton hotel in San Diego, said he found a resale single house priced about $55,000, but had to spend a few thousands to bring it up to par. "It's not as much house as the one we sold last year in Tulsa for $38,000, but we like it here," he added.

Up in Orange County, where the Irvine Co. is developing a massive, long planned community on more than 77,000 acres of what had been mostly farmland, marketing executive Frank Hughes said that winter delayed construction of homes, most of which are now priced above $100,000.

He said that traffic has slowed but there still is a strong demand for new half-acre Harbor View lots priced from $150,000. There are still waiting periods for smaller, attached houses.

George Fulton, vice president of Walker & Lee, which markets both new and used houses, commented: "IRS is subsidizing all housing today. Owners in their own houses get a break on taxes and mortgage interest as deductions. Yet there's also a big rental market for the single houses that people buy as investments. You can't rent a $100,000 house for enough to carry the monthly payment of the owner so the tenant actually gets a break in the rent because the owner has depreciation and a negative cash flow - betting on appreciation up the line on resale."

Housing statistics executive Stephen Ballas said he buys new houses, rents them and sells them after a few years. "Because of my work, I know the market and can tell the best buys when subdivisions are opened. Inflation has pushed up appreciation in recent years so there have been some nice profits."

But Ballas and others are aware that mortgage lenders have been getting tougher on investor-speculator buying of new houses, a phenomenon that became acute last spring in Southern California. Construction and land development costs still are rising but much of the zing has been taken out of the new-house boom that also heated up the resale house market.

In northern San Diego County, where Rancho Bernardo was started 15 years ago as a middle-class new town in the hills, even the small new singles approach $100,000. The middle-market now ranges from $80,000 to $120,000. Yet there are families and individuals in Rancho Bernardo who are getting $75,000 for houses that they bought in the 1960s for less than $30,000. Incidentally, RB has two sections for "adults only" as an alternative to other total adult communities such as big Rossmoor at Laguna Beach.

Inquiring visitors to the Orange County and San Diego areas find more than high prices, basementless houses, orange tile roofs and an absence of gutters and downspouts. The landscaping around even modest-priced existing houses is abundant and near-tropical. But nearly hills, now greener than usual, are somewhat barren, and the new town and far-out suburban areas have been fewer persons than one might expect to sight on even a rainy Saturday or a sunny Sunday. Generally, houses are built close together or on zero lot lines, but there's lots of open, undeveloped space between neighborhoods.

Meanwhile, there is abundant evidence of increasing commercial-industrial competition in the area south of Los Angeles to the Mexican line. San Diego Mayor Pete Wilson recognizes that his city has attracted many thousands of new residents since 1970, including 20 percent who are retirees forsaking the snow scenes. "Right now California needs manufacturing jobs,"says the Ivy League lawyer.

In the spring primary, Californians will vote on a proposal to hold the maximum residential realty tax to one percent of the true market value of a property. It's more like 2 percent now, and taxpayers have been organizing and grumbling. At first, Wilson liked the proposal but changed his attitude on the basis that a smaller tax intakes on properties merely would shift the burden elsewhere.

On one hand, encountered Californians are disturbed by high taxes, the high costs of houses and a nagging fear that the bubble could really burst and take away paper profits. Yet, mid-road, young professionals like the fact that their area is attracting people from elsewhere and providing a climate where they can spend little on heating and air conditioning and have an opportunity to work and move up in class.

And don't believe that these leisurely dressed Southlanders don't recognize status symbols. They tend to worship imported cars, three-car garages, tile and cedar shake roofs and cathedral ceilings.

Marketing researcher-investor Ballas put it this way: "Point Loma (San Diego) is a nice area, but the same house in LaJolla will bring $20,000 to $30,000 more. Small businesses establish their addresses in LaJolla just to get the magic zip code" (92037).

Another somewhat high-status address by the freeway on the southern tip of Orange County is a small retirement community oriented to the Pacific. It's called San Clemente and it has a turnoff to Presidential Boulevard. You can see the Nixon place behind the walls that make it a compound.