RECREATION IS the nation's No. 1 industry, surpassing defense, home building and automobiles, according to a recent survey of leisure-time activities.

And the Washington area's public recreation facilities and programs are among the most sophisticated in the country.

Pre-capita spending in the Washington area ranks among the highest in the nation, the National Park and Recreation Association reports. Arlington, for example, with a population of 159,000, has a larger operating budget for parks and recreations than any other city of 100,000 to 250,000 people.

The public recreation industry in this area is loaded with innovative administrators, structured programs and taxpayers willing to ante up for the services, a Washington Post survey revealed.

For example, Fairfax County voters last month approved a $51.1 million bond referendum for parks and recreation. That includes $39 million to develop community parks over the next five years.

"You can't do anything unless you have the money. This is very prosperous area and the people want this kind of recreation," said Joe Downs, director of the Fairfax Park Authority, in an interview at the county's plush $6.5 million Wakefield Community Center.

Americans will spend $160 billion on leisure-time activities this year, according to copyrighted figures by the U.S. News and World Report's economic unit. That's for everything, right down to the plastic worms an angler throws at largemouth bass. The magazine estimated spending would reach $300 billion by 1985.

And recreation programs are growing up. No longer are administrators simply opening the door and throwing out the ball, as was the case less than a generation ago.

"People were aware of the need for recreation then," said Dr. Ira Gabrielson, the 89-year-old chairman emeritus of the Northern Virginia Park Authority Board. "But it's more organized now."

Organized means expensive. In the Washington area, public recreation agencies will spend close to $125 million in operating expenses for fiscal 1977. That does not include costs for land acquisition, construction and equipment purchased by the public.

The focus and services run the gamut from D.C.'s highly-acclaimed Roving Leaders program for guiding youngsters to the Northern Virginia Regional Park Authority, which serves as much as a conservation agency as a recreation outlet.

Every area jursidiction has programs for all age groups, although the National Park and Recreation Association says adults aged 20-40 are the segment of the population most neglected by public recreation agencies.

Locally, the federal government provides the most money and the most land for public leisure-time activities. The National Capital Region of the National Park Service operates on a $40 million annual budget with more than 55,000 acres of parkland in the District, Maryland and Virginia.

The National Capital Region is unique among regions of the National Park Service; it is the only one that provides community-oriented programs such as the Summer in the Parks, which includes a Shakespeare festival and free concerts by the National Symphony.

The Park Service also supervises the popular picnic groves in Rock Creek Park. Manning Mosley, chief of the Branch of Community Program for the National Capital Region, said every reservable picnic site was gobbled up for every summer weekend by mid-May this year.

But the local boom also has spawned problems, according to the Post's six-week survey. Those problems are nurtured by that root of much evil - inflation.

Local jurisdictions are feeling the crunch from decreasing mobility of populations as transportation costs go up. The result is a stampede on local facilities and a willingness among taxpayers to spend more money for community parks.

As recently as 1965, a survey by the Interior Department reported, the No. 1 outdoor recreation activity in this country was getting in the car and going for a drive. Those days are over.

With the new play-close-to-home mentality, local jurisdictions are facing unprecedented demands for facilities and manpower. Some, such as the rich Maryland suburb of Montgomery County, are facilities poor. The thinking a decade ago was that country clubs would take up the slack. Today, Montgomery residents want public facilities and they're not there.

Other jurisdictions with better facilities back the money to operate them at hours during which most working people can use them - late evenings and weekends.

Prince George's County last year began opening the Prince George's Plaza Community Center from 10 p.m. to 3 a.m. for people over 20 years old. The idea was to accommodate shift workers such as police, fireman and postal workers.

The innovation was a success, but a recent $2 million cut in the county's recreation and parks budget now imperils the "night owl" program and has ended plans to open another late-night center in the southern part of the county.

The cost of land-acquisition is high, too. The Northern Virginia Regional Park Authority recently paid $80,000 an acre for a 26-acre tract, and Arlington County paid $750,000 for three acres near Crystal City.

The taxpayers would howl at such a cost for a community center, so Arlington planners took an innovative approach, according to William Hughes, director of the Department of Environmental Affairs which over sees parks and recreation.

The new facility, called Aurora Hills, will houses a branch library, a fire house, an air monitoring station and a visitor's bureau, as well as the community recreation center, thus cutting maintenance expenses.

Some smaller localities are supplementing services provided by county agencies. For example, Herndon, Va., which grew rapidly in the last five years, established its first department of parks and recreation of year ago. Three months ago the townspeople approved a $3.5 million parks referendum, which is built around a plan to put the town into the golf course business.

Through this venture, Herndon expects to build an $850,000 community center, increase property values and pay off the bonds in 30 years through revenues from the golf course.

Historically, recreation and parks departments have been slow to respond to national trends and priorities. Mosley of National Capital Parks said that is a major reason why public recreation budgets are the first to be cut in a dollar crunch.

Yet, as U.S. News and World Report notes, recreation is the country's biggest industry and will continue to surge as the nation moves toward adhering to a leisure ethic as well as a work ethic.

"People don't realize what that $160 billion-a-year figure means to the economy," said Mosley, "because it's usually the first thing to get cut in the budget. But the ripple effect is felt across the community." CAPTION: Picture 1, The pool at the $6.5 million Wakefield Recreation Center is cool on hot July days. By Craig Herndon - The Washington Post; Picture 2, Director Joe Downs of the Fairfax Park Authority checks out kids' likes and dislikes at his pride and joy, the plush Wakefield Center. By Craig Herndon - The Washington Post