Westheimer Road, the main drag of Houston's booming Montrose section, is a wild melange of residences, artsy shops, homes turned into restaurants, hamburger stands, banks and gas stations.

Cheek by jowl with Alma Robinson Antiques is a place called L'Amour, advertising "totally nude girls." Across the way is a Don's Le Patois, a fancy French restaurant; just down the street are the Happy Buddha Steak House and Phoenix Books. And within a block are chic new townhouses, restored garden apartments and duplexes.

One can imagine the zoners and professional planners muttering about "incompatible land uses." But that, Houstonians will tell you, is precisely the point. Virtually alone among major U.S. cities, Houston has no zoning, has never had zoning. So when the free market decides a declining older neighborhood like Montrose is ready for investment and revival, there are no encumbrances: The money can flow, the city can be recycled.

Houston urban planner Dick Bjornseth recommends that planners across the nation, who have long disdained Houston and its lack of controls, stop telling Houston "to get in step with the rest of the country and get in touch with us instead."

The idea of junking zoning, the accepted method of urban land-use control from coast to coast, is something of a shocker. But the nonzoning, gospel, developed by Bjornseth, author Bernard Siegan and others, deserves a careful hearing.

Zoning, they argue, is responsible for a host of evils:

Inflated housing costs. By artificially limiting the amount of land available for apartments, zoning restricts the supply and thus increases the costs for renters. The same applies to single-family houses: By limiting housing density, zoning forces larger lots than the market would demand, again forcing up prices for the consumer.

Dull, monotonous housing developments. Zoning regulations force uniform height of buildings and specify to the minutest detail setbacks, square footages, side-yard distances and the like. But in a nonzoned city, there's far more competition; a developer has to pay more attention to aesthetics, including landscaping and overall visual appeal, to respond to the requirements of the marketplace.

Urban sprawl and energy waste. Zoning makes it far more difficult to recycle low-density residential areas of older inner cities into apartments and townhouses that accomodate more residents. In the suburbs, it forces larger-than-necessary house lots. As a result, the city spreads out faster than necessary; people live farther from work than they need to and enormous energy waste results.

Houston itself is poor advertising for energy conservation; it is one of the nation's most profligate energy users. But that's probably due to its supercharged Sunbelt economy, its population boom and status as de facto energy capital of the nation - not the absence of zoning.

Unnecessary bureaucracy and regulation. Writing zoning plans and trying to enforce them requires immense bureaucracies that strapped local governments can ill afford. Every parcel of land, whether vacant or improved, must be classified. The result is often an administrative nightmare.

Chicago has two single-family zoning districts, six multifamily, seven business, four commercial and three industrial districts - many with subdistricts - for a total of 70. In the B1 district (local retail) you can open a barber shop, drugstore, grocery store or even a college - but not an art-supply, book, ice-cream or hardware store. In any event, your maximum floor area is 6,250 square feet.

The reasons for such weird divisions and requirements seem discernible to planners alone. Or as Siegan charges, zoning often boils down to "regulation for the sake of regulation."

Politics and graft. A really sound zoning plan, taking into account every factor of changing consumer preference, equity, future economic trends and needs of a city, is a virtual impossibility. So planners have to operate largely on guesswork. And that assumes they are left alone to mediate and contemplate - which they are not. Because there's simply too much money and power at stake, powerful economic interests intervene. The opportunities for graft have fostered suburban outrages to equal the worst of old Chicago.

Prejudice against the poor and minorities. Through such devices as one and two-acre lot requirements, suburban zoning is a monument to racial and economic discrimination. Court challenges to exclusionary zoning have begun to succeed - but change is glacially slow.

City zoning, too, often represents some middle-class planner's idea of the good society and ignores poor and blue-collar people's needs: to have close-by factories and other places of work, grocery and hardware stores and neighborhood pubs, to get their own start in business with a "ma and pa" store on the ground floor of their residences.

In rundown city areas, zoning may protect - at least temporarily - poor tenants from eviction when a developer casts covetous eyes on their area. But even in zoned cities, urban renewal causes such evictions. The answer lies in providing alternative housing, not land-use freezes that stop economically beneficial recycling of the city (including new job opportunities and bolstering of the tax base).

Many people say zoning is needed to stop factories in the midst of quiet neighborhoods. Houston's heavy industry, however, congregates along major highways, waterways and railroad lines - as industry does everywhere. There are a few eyesore exceptions, but gas stations and auto-repair shops and fast-food operations generally seek out heavily traveled roads, leaving purely residential areas alone.

Houstn is not totally without controls. New subdivisions adopt restrictive convenants to prevent unwelcome intrusions (though the convenants apply to only a quarter of the city's land, compared with zoning's 100 per cent coverage in other cities). The city has a building code and regulates subdivisions, the location of slaughterhouses and mobile homes. But the weight of regulation is light compared with that in other cities - setting the scene for the kind of economic rejuvenation so desperately sought elsewhere.

Land-use controls are doubtless vital for flood plains, for areas of natural city beauty and urban areas imperiled by urban sprawl. But do we need across-the-board zoning? The Houston success story is strong enough to suggest that zoning may be the land-use dinosaur of the '70s.