Decades of conspicuous consumption, throw-away products and enormous waste are beginning to catch up to America. The coming national crisis may be one of garbage - chiefly, where to put it.

There are growing piles of radioactive nuclear waste but no agreed-upon N-dumps in which to store it. Toxic wastes present their own problem. And even ordinary garbage is becoming a threat.Tighter environmental controls and space restrictions are making the city dump a dinosaur. Up to one-third of the nation's 6,000 garbage dumps are expected to shut within five years, forcing communities to find new ways to dispose of their garbage.

Incinerators have been touted as a way to produce energy while reducing garbage. But questions about air quality and the disposal of byproducts laced with toxins persist. Burning isn't always the best solution.

Recyling is offered as one answer. That calls for products to be reused instead of buried or burned. But recycling also requires extensive separation of garbage into different categories before it is collected.

Every American man, woman and child generates 3.5 pounds of refuse a day - adding 160 million tons to the nation's trash heap every year. Only about 10 percent is recycled - although studies suggest as much as 86 percent of household trash is recyclable.

Will recycling be the wave of the future? Only time will tell. Ten states already require - or will soon require - residents to separate newspapers, glass jars, milk cartons, tin cans or other discarded items for recycling trucks or bins. Legislators in 33 states are expected to consider plans to increase recycling this year.

Whatever the answers, it is going to cost money. Tossing out the garbage will have to be paid for. This is giving rise to new kinds of companies, and some are reaping significant profits - especially those that deal with hazardous waste.

Almost everything America consumes - from pharmaceuticals to consumer products to even decaffeinated coffee - produces hazardous waste that must be disposed of. Hazardous waste processing will be a $5 billion industry this year, and that number is likely to more than double by 1994.

The hazardous waste disposal industry already claims several millionaires. Companies specializing in infectious waste, radioactive contamination and dirty drinking water are in high demand.

So are places to dispose of the stuff, which makes the wide open spaces of Utah and other Western states such attractive targets for Easterners, many of whom tend to think of the empty areas as useful garbage dumps. It's an attitude that has to be opposed at every turn.

A high standard of living is wonderful, but it won't last if it continues to be careless, wasteful and geared to throw-away convenience. America is searching for a way of disposing of its trash, but the best answer would be not to produce so much of it.