Accusing a Pride, Inc. affiliate of mismanaging the problem-plagued Clifton Terrace Apartments and owing $300,000 in back mortgage payments, the U.S. Department of Housing and Urban Development has decided to foreclose on the project, according to informed HUD sources.

The decision marks the second foreclosure attempt in five years for Clifton Terrace, one of the nation's first major inner city rehabilitation projects. It has been managed by P.I. Properties, an affiliate of Pride, since May, 1974, and owned by P.I. Properties since June, 1975.

Informed HUD sources said the decision to foreclose on Clifton Terrace, a 285-unit apartment complex at 14th and Clifton streets NW, came after protracted negotiations and was "agonizing to go through." It came, said one source, when negotiations with Mary Treadwell, head of Pride, Inc., the self-help organization which helps train youths for jobs, reached an impasse. HUD felt it had no other alternative but to foreclose after Treadwell refused to allow another firm to manage the complex, one source said.

Treadwell, executive director of Pride and president of P.I. Properties, said yesterday she plans to fight foreclosure. Treadwell blamed HUD for many of Clifton Terrace's problems, contending that many of its deficiencies reflect "fraudulent" rehabilitation work done by construction firms under contract with HUD several years ago, before P.I. Properties began to manage or own the project.

Treadwell, who said she is being used as a "scapegoat," said that HUD's action "is a typical example of how and why HUD ends up being the nation's slum landlord."

From years, the problems and successes of Clifton Terrace have been watched closely by federal and local officials. It was felt by many that if the project, aimed to aid low income families, could be successful, especially under the ownership and management of a community-based minority organization, it would serve as a model for the nation.

Eleven years ago, Clifton Terrace composed of three dingy beige five-story buildings, was one of the city's most notorious slum properties, known for its rats and building code violations.

By November 1975, however, things had improved to the point that when Mayor Walter E. Washington toured the buildings, he praised them as a model of how to provide low and middle income housing, claiming that they met a housing need and showed that black "entrepreneurship" can work in the inner city.

But the story is different today. Beneath a sing proclaiming "The new Clifton Terrace West" at one building, doorways to the lobby have broken and missing windows. All three buildings, have other missing items - door handles, mailbox doors, elevator buttons, fire extinguishers. One building has fire damage visible on the top floor. Graffiti fills the walls in places. Random holes are punched in the walls in other places. The odor of urine lingers in some elevators and hallways.

Ironically, Clifton Terrace was built in 1916 as the largest luxury complex then in Washington. Between 1962 and 1968 it began to deteriorate, and its population changed from predominantly white to predominantly black. One of its owners was sentenced to 60 days in jail in 1967 - time which he never served - for failing to provide heat for the tenants, and housing inspectors that year found more than 1,200 building code violations.

George Blackwell has lived at Clifton Terrace since 1963. "I was the second colored to move in," Blackwell, a short, articulate man said. "It used to be lily white." Blackwell is one tenant who has complained over the years about managementof the complex where rents range from $138 a month for an efficiency apartment to $210 a month for some four-bedroom units.

Tenants often have gone without heat during some of the area's coldest winter periods and were informed last week that there will be no air conditioning this summer.

"We're getting no services," Blackwell said. "Once they (the property managers) walk out the front door, they couldn't care less about the tenants who live here.

"I can get sick just looking at the outside of these buildings. The smell takes your breath away if you walk up the steps. We want new management, and we'd like to know what's being done with our money," Blackwell said.

Mary E. Taylor, who lives on the fifth floor of the 1312 Clifton St. building with her seven children and one granddaughter, remembers that when she moved there in 1972, it was like a mansion. Now you wouldn't believe it. It's pitiful. There's no security, no maintenance. The trash chutes are so full you couldn't put trash in it. I'm living in something I wouldn't want a dog to live in."

Taylor, and other tenants interviewed, also complained of attempted rapes and said security guards assigned to the buildings are often unavailable.

There are maggots in the trash chutes they said. One tenants, Anna Burris, said that during a nighttime fire, tenants were "falling over each other" trying to get down the stairway because there were no lights to guide them.

A notice distributed by the Clifton Terrace Tenants Association urging residents to "raise hell" about conditions, list 10 problems. Number 1 was filthy floors and halls, number 6 was rats, number 7 was roaches. Number 10 said simply, "On and On and On and On . . . ."

After an audit of Clifton Terrace by a HUD inspector last summer, HUD claimed P.I. Properties' financial records were "incomplete, inaccurate, and in some instances, could not be located." The audit report said costs were charged to the Clifton Terrace project which should have been charged to other housing projects managed by P.I. Properties, costs were charged which were unnecessary for project operation, and there were no indications the managers solicited bids to obtain lower prices. At that time, there was a mortgage default of nearly $200,000.

Bryant and Bryant, a local architectural firm, recently conducted an inspection of Clifton Terrace. Its report cited $774,900 worth of needed repairs and said there were damaged windows, few handrails, malfunctioning downspouts, broken steps, missing railings, exterior window and door openings that permitted rain to enter and problems with elevators.

P. I. Properties has managed Clifton Terrace since May, 1974. The Housing Development Corp., a non-profit housing corporation, had bought the complex in 1968 and received a rehabilitation loan insured and party subsidized by HUD. HDC soon ran into financial problems, however, and HUD foreclosed on the property in 1973.

In June, 1975, Clifton Terrace was sold to P.I. Properties for about $820,000. It was sold to the Pride affiliate, one HUD source said, because the firm "was looked upon as a community-based organization that could create an important relationship with tenants as well as be good managers." Clifton Terrace instantly became a "cause celebre," the source added, a "symbol for revitalizing cities and in how to provide low and moderate income housing. It was important."