The Urban Institute has studied New York City and found -- as many others have noticed -- that the city is wearing out physically.

Washington's prestigious institute for research on urban problems issued a report today saying that if levels of spending to replace worn-out public facilities cannot be increased. New York is headed for serious problems.

Years before New York plunged into near-bankruptcy, the city chose to neglect maintenance and replacement of its physical plant in favor of building new projects.

Politicians preferred adding new schools, fire houses, police stations and hospitals which their constitutents demanded rather than replacing sewer pipes or repainting bridges.

The city's 6,000 miles of streets, 1,322 bridges and tunnels, 230 miles of subways and roughly 6,000 miles of water mains were locked into a state of disrepair when the fiscal crisis forced capital spending cutbacks beginning in 1974.

The report says New York's deteriorating infrastructure "needs a significantly increased rate of investment in maintenance and replacement if serious problems are to be avoided in the coming decades. It is a crisis that should be viewed in terms of years or decades -- not days or months."

Any rider on New York's streets knows they need extensive repair. Although the city fills about one million potholes annually (one for every 30 feet of roadway), the report says that perhaps one-third of the streets need complete reconstruction.

At current rates, each street would be rebuilt every 150 years. Robert F. Wagner Jr., chairman of the City Planning Commission and son of former mayor Robert F. Wagner, has said that ideally streets should be replaced every 20 to 25 years.

The streets, water, sewer and transit systems are the four main areas examined by the report which reinforces the conclusions of studies that have been made by the city.

Wagner said shortly after the administration of Mayor Edward Koch took office last year that "rebuilding our physical plant is second only in priority to resolving the fiscal crisis."

The collapse of the elevated West Side Highway was the most dramatic example of New York's physical decay. Poor construction coupled with inadequate maintenance have forced the city to begin tearing down a road-way that was built only 40 years ago.

One of every 10 bridges and tunnels was found to need major repairs or replacement in a 1977 inspection and 13 percent were listed as needing less major work.

Under the city streets the problems may be even more serious. The report says that it is difficult assessing conditions or planning future investment because much vital data is unavailable. For example, the city has no standard map of street boundaries and the underground utilities -- different departments each have their own.

Under a single street there can be water mains up to six feet in diameter, storm and sanitary sewers, electric, telephone and telegraph conduits, fire alarm signal lines, steam pipes and more than one four-track subway, a subterranean infrastructure as complex as any in the world.

The most ominous, because least understood, potential problem is in New York's water supply system.

All the city's water passes through two huge tunnels before entering the complex of smaller water mains. Neither of the tunnels can be closed for maintenance without depriving roughly half the city of water and no one knows what condition they are in.

They have been in constant use for over 40 years.

Engineers don't dare close off even a small section of the water tunnels where there are existing bypasses because they are afraid that the valves will stick in the closed position, the report says.

Construction of a third water tunnel that would have enabled either of the old ones to be shut for periodic maintenance was halted during the fiscal crisis. By present estimate it would cost $600 million to complete the first stage of the new tunnel and another $600 million to extend it to lower Manhattan, the report says.

No such funds are available and the city budget item for the tunnel is only enough to keep the completed construction from deteriorating.

The smaller water mains, many of which were installed in the last century, are being replaced at a rate that would renew the entire system only every 200 years, the report says.

In recognition of its needs, New York has issued a 10-year forecast of capital spending that would reverse the trend of the last decade.

Nearly half of all city capital funds went to education, transit and pollution control in the last 10 years. For the future, city planners would cut this to about 10 percent and spend more than 60 percent of capital funds on repairing water supply systems, seweris, highways and bridges.

The Urban Institute, a Washington-based nonprofit organization seeking solutions to urban problems, plans a series of reports on the condition of physical assets in older American cities.

David A. Grossman, a former New Text Omitted