Like an invisible cloud, a phenomenal increase in heroin has enveloped Washington's inner city, supercharging street drug life with new activity, taxing police containment efforts to the limit and jamming addiction treatment centers with a new generation of junkies.

Heroin has been pouring into Washington in greatly increased amounts since late last year. This is apparently the result of increased production in the poppy fields of the Middle East and Southeast Asia, according to local and federal drug enforcement authorities.

"The world market of heroin is up, so it's up here," says Lt. Mike Hartford, head of the D.C. Police Department's inner-city 3rd District narcotics squad.

The result: the tempo of street life is up. The buying and selling of heroin has intensified. The price is low and the purity higher than usual, a sure sign of a glut, Hartford says.

Crime is up. Police report dramatic increases in housebreaking and shoplifting -- the two crimes most commonly associated with addicts seeking to support their habits.

Overdose deaths are up. The number of heroin-related deaths in the city quintupled from three in the first half of last year to 15 in the first half of this year, according to the D.C. Medican Examiner's Office.

Anxiety is up, too. A well-dressed woman paces the sidewalk at 14th and R streets NW, looking impatiently for her connection. Knots of men gather at corners and in alleys throughout Shaw and Cardozo waiting for their "juggler" to deliver the thin transparent packets of the highly addictive white powder.

The ebb and flow of life on 14th Street, the longtime center of drug traffic in black Washington, has changed -- at least for the moment.

A current police crackdown on 14th Street scattered many of the addicts, dealers and runners into the surrounding neighborhoods and nearby alleys, abandoned buildings and rubble-strewn vacant lots. They occasionally drift back to 14th Street only to be swept away again by special patrols of uniformed police officers.

At the other end of the addiction cycle, city narcotics treatment officials are seeking a vast influx of new addicts seeking help.

The substance abuse administration of the Human Resources Department is treating almost 2,000 addicts, an increase of more than 700 since this time last year.

Its central intake office at 1714 14th St. NW took in 20 or more addicts a day on several days last week, double the average intake. All treatment facilities are approaching capacity.

Officials are quick to say the current increase is nothing like the near epidemic of heroin addiction that raged through the city a decade ago. A sharp decline followed in the early 1970s, however, and officials are disturbed at the similarly steep increase now after several years with a relatively small and stable addiction population.

Particularly disturbing is what appears to be an upsurge in novice or first-time users of heroin -- a still uncounted population of youthful experimenters and weekend "chippers" lured into the shadow world of heroin by its easy availability.

"The new significant indicator is the new admissions [for treatment]," says George Powell, director of the city's 14th Street intake office. "We're getting a lot more than we used to . . .and they tend to be younger than readmissions [addicts formerly enrolled in treatment who drop out but return for subsequent treatment]."

Heroin use is primarily a black phenomenon in Washington. The typical user is a black male in his 20s. And when there is a sudden increase in heroin availability, as now, say Hartford and others, the dealers and setters begin looking beyond their regular customers to younger, more impressionable novices to make their sales.

Little is known about this new population of addicts. Officials are cautious in characterizing them, except to say they appear to be younger with some perhaps better educated in a formal sense but lacking the street savvy to avoid heroin.

"A lot of national and international dealers regard Washington, DC., as a narcotic gold mine. . .because it's a heavily black city, says Gen. Hassan Jeru-Ahmed, head of the Blackman's Development Center and a veteran street observer of the drug scene.

The rising crime rate, increased overdose deaths and growing addiction treatment population are supported by other statistical indicators suggesting a marked upsurge in heroin availability here.

The percentage of the treatment population showing heroin traces in urine samples is up 15 percent this year over last year, Heroin traces in urine samples of criminal defendants who are procedded through D.C. Superior Court also are up, though not as dramatically.

D.C. police narcotics detectives have sharply increased the number of seizures and undercover "buys" of heroin.

The average price for a milligram of heroin obtained in undercover buys has fallen by more than half from $7.71 in the first quarter of 1978 to $2.64 in the first quarter this year, according to police figures.

At the same time, the so-called purity of heroin in the city has increased from less than 2.5 percent early last year to an estimated 3.5 percent this year. (Pure heroin is heavily "cut" or diluted with quinine, milk, sugar or other elements to make is palatable and nonlethal. The higher the purity, the stronger the "rush" effect.)

Police say that the combination of lower price and higher purity is a strong indication of increased availability of heroin in the city.

Hospitals in the city also report an increase in the number of "episodes" involving heroin in their emergency rooms, that is, cases of people treated for some illness related to use of the narcotic. The number of cases jumped from 30 at seven major hospitals, including D.C. General Hospital, in the first quarter of 1978 to 46 in the first quarter this year, according to the U.S. Drug Abuse Warning Network.

Kurt Brandt, medical director at the city's substance abuse administration, says the current upsurge in addicts seeking help is caused, ironically, by what appears to be a temporary shortage in the generally increasing supply of heroin on Washington's streets.

"When heroin increases, more people get addicted," he said. "Then when the supply dips, the people start coming in here. . .They can't get their regular supply and they start to get sick."

He said, "There is no doubt there has been an overall general increase [in heroin], an upward trend, but there are also fluctuations within this larger trend."

Brandt also said a recent crackdown on drug pushers and prostitutes along 14th Street by 3rd District police is "driving people in here for treatment."

Praising Mayor Marion Barry for ordering the crackdown, Brandt said addicts report that their regular dealers have been scattered and it is increasingly difficult and risky to find them.

He acknowledged that some addicts may seek treatment only temporarily, with the intention of returning to the street once their regular supply is reestablished.

Addicts seeking treatment are given, among other things, daily doses of methadone, itself a highly addictive synthetic drug that blocks the craving for heroin.

Police officials view the 14th Street crackdown, which resulted from pressure brought by merchants in the area, as only a stopgap measure. It pushes the problem into other parts of the city but does not solve it, they say.

"The people we arrest and talk to tell us it's harder now [to buy heroin]," says Lt. Hartford of the 3rd District. "They gotta be more careful. . .And of course, the merchants are happy. They don't have a bunch of junkies standing in front of their door. . .We've pushed them away.It [the crackdown] may actually discourage your borderline users, the weekend chippers, but you're never gonna stop these hardened addicts. . .They're gonna get it somewhere."

Hartford also questioned the conventional wisdom that addicts are responsible for increases in crime.

"I don't know, that that's fair," he said. "It always been a nice cliche . . .but some [addicts] don't have the heart to break into somebody's house. . .A lot of the ones I know, they sell drugs to get drugs. Some of them have whores that turn tricks for them. That's how they get their money."

Hassan agrees that much of that is true, "but there's plenty of stealing that goes on, too," he says.

"Did you ever notice how there aren't many people hanging on the corner out there around noontime" says Hassan, looking out from his Blackman's Development Center office at 14th and R streets NW. "That's because they're downtown boosting [shoplifting] in the stores. They go down there at noontime when the store clerks are on lunch break and there aren't so many people in the stores."

Brandt at the treatment intake office says the typical heroin addict in Washington now has an $80-a-day habit. "Eighty dollars will buy him about. . .10 milligrams, which he divides into four doses. He takes one dose about every six hours by injection."

"Eighty dollars a day," muttered Hassan. "That's a lot of boosting."

Federal drug enforcement officials agree with local police that the purity of local heroin has increased in recent months. In addition, notes David G. Canaday, special agent in charge of the Washington district office of the Drug Enforcement Administration, so called white heroin from Southeast Asia appears to have replaced brown heroin from Mexico, called Mexican mud, as the principal type of heroin distributed here.

"Almost all our intercepts here are white heroin," Canaday said.

Border enforcement and a crackdown on poppy fields by Mexican authorities has severly reduced Mexican mud imports, he said.

Most white heroin originates in the "Golden Triangle," a remote hilly area in Southeast Asia where the borders of Thailand, Laos and Burma come together. Canaday and other federal officials said, however, that additional supplies of heroin are now coming from poppy fields in the Middle East, particularly Pakistan and Afghanistan.

Some of the Middle East heroin may now be reaching eastern U.S. cities, possibly increasing availability of the drug in Washington, Canaday said.

Hartford said there is "no Mr. Big running things in Washington...We have a lot of independent operators working. They all got their own connection" in New York or other large eastern U.S. port city for receiving smuggled heroin.

"Some go to New York," he said. "Some go straight to Amsterdam in Europe to get it."

Whatever the source, heroin is on the upswing here, Hartford said, and thousands of people are getting hooked on it.

"They're chasing that high," he said. "They can't face reality."