Court-sanctioned federal, state and local government housing policies have contributed to growing racial and economic polarization and to the decline of the nation's cities, an American Bar Association study issued today says.

The 619-page report by the ABA's Advisory Commission on Housing and Urban Growth charges that government at all levels has engaged in overt and covert discrimination - "on the basis of race or income disparities" - in setting housing policies.

While the more blatant forms of racial discrimination are "now universally prohibited" in governmental housing programs," economic discrimination is not," the report said. "And economic discrimination often has the same effect - and at times the same motivation - as racial discrimination," according to the report.

The document was prepared over the last three years by the 22-member commission and a 12-member staff. It contains charges against governmental housing policies - a number of them old charges - such as financing highway systems that aided suburban growth and urban decline and recommendations that are expected to spark controversy, particularly in judicial circles.

For example, the report accuses the courts of frequent bias in cases brought to change zoning and landuse practices that limit housing opportunities for minorities and low-income people.

"In the last 50 years, there has been a strong jucicial bias against those attacking land-use regulations," the report said. "It is more than a plaintiff's initial burden of proof. Most of the courts . . .have attached a presumption of validity to the municipal regulation, thus elevating to the highest value those community judgements that are expressed through the locally elected legislative body," the report said.

As a result, "purposefully exclusionary (municipal) land-use policies" abound throughout the country, the report said. According to it, these policies include:

Minimum house size requirements. "The most direct and effective exclusionary tool" because it pushes construction and housing costs beyond the reach of the low income.

Housing prohibitions which restrict developments to single-family units, thus effectively eliminating "the most realistic opportunity for housing persons of low-and moderate-incomes" who can better afford multi-family dwellings.

Prohibition of mobile homes. "As the average price for a single-family conventional home continues to climb beyond the reach of a large proportion of the population, the only available nonsubsidized form of housing for those persons who wish to won rather than rent is the mobile home."

Unnecessarily high subdivision requirements. Community ordinances requiring developers to provide land improvements (open space and recreational facilities) "far above the necessary minimum." The report said such requirements also drive housing prices beyond the reach of the low-income.

Administrative "delays, the imposition of arbitrary development demands in exchange for local permits, and other local practices (that) can also be used for exclusionary ends."

The widespread use of such policies is reflected in places like the New York City metropolitan area, where 99.2 per cent of the undeveloped land zoned for residental purposes is restricted to single-family houses; like Connecticut, where more than half the vacant land zoned for residential use is one to two acre lots; and Montgomery County, Maryland, where a moratorium on sewer connections has driven up housing costs and socioeconomic conditions, according to brief examples provided in the report.

If such zoning regulation continues and if current patterns suburban of growth continue, "greater numbers of Americans will be denied housing choice, our cities will continue to deline, and racial and economic segregation will be perpetuated," the report said.

To help remedy those problems, federal and state courts - which have jurisdiction over land-use should broaden their interpretation of land-use law to include more than the two "fundamental values" of the rights of property owners to use their property and the rights of local government to regulate private property, the report said.

Specifically, opportunities for decent living accomodations in decent enviroments, freedom from legally imposed discrimination based on income, and access to employment and educational opportunities are fundamental values that must be given equal consideration with values related to private property rights and to municipal self-determination in making land-use decisions," the report said.

The commission noted the controversial nature of its recommendation, saying that there will be some who "will argue that to expand the scope of judicial concern beyond the scope of private property rights and municipal self-determination is to embark on a course of unprecedented and unwarranted judicial activism that would be better left to state and national legislative bodies."

"A short reply would be that state and national legislatures have (generally) displayed a reluctance to take strong affirmative action" to correct exclusionary land-use practices, the commission said.

Other commission recommendations included:

More effective use of federal and state powers to prod reluctant suburban communities into meeting their "fair share" of low- and moderate-income housing.

Requiring governmental bodies to give adequate notice and to provide public hearings before denying or approving housing developments and land-use plans.

Creating local and regional land-use plans designed to help central city and suburban areas.

Increasing state involvement in providing housing opportunities for diverse income groups.