Three years ago Janice Washington decided she and her fellow tenants should buy their small Northwest apartment building when it was put up for sale.

She knew they needed a lawyer and knew the six tenants, with incomes of less than $15,000 a year, could not afford one.

Somebody told her about University Legal Services, a nonprofit legal organization that specializes in representing low income people with housing problems. ULS helped the tenants buy the building at 539 Newton Place for $75,000 and last week ULS was still helping the tenants, this time trying to settle a contract dispute.

"I never expected to own my own home," Washington said recently. "We couldn't have done this without University Legal Services. They were with us every step of the way."

For 18 years University Legal Services, which was founded by two Catholic University priests, has been helping tenants faced with landlord-tenant disputes, housing code violations, displacement, or sale of their apartment buildings.

"We are a nonprofit law firm that specializes in housing problems of low income people," explained Howard Lewis, executive director of ULS, located at 324 H St. NE. Lewis oversees a staff of 17, including six lawyers and four housing counselors.

"Right now we're working with 28 tenant groups; four groups purchased their buildings during last summer," explained Holly Malloy, assistant director for legal services, who oversaw those purchases.

But the organization's success is causing problems. Lewis said he is concerned that ULS is falling into a financial crisis because "our caseload is growing faster than our private donations and regular funding sources," he said.

The organization's budget of $360,000 includes $212,000 from city and federal funds, $12,000 from the D.C. Bar Association and private donations.

The number of clients has jumped from 1,256 in 1980 to 5,562 in 1985. "People who are poor who have problems with their landlords, or who want to purchase their house simply have nowhere else to turn for free legal service," Lewis said.

To qualify for ULS services, a single person is not to make more than $12,550 annually and a family of four should make less than $17,900 a year. Some exceptions are made, including one for Janice Washington's group.

Much of the work involves helping tenants buy their apartment buildings. Under a city law, a landlord must first offer a building to tenants when the property is put up for sale. If the tenants can match the price offered by another buyer, the tenants get to buy the building.

Working with MUSCLE, a nonprofit housing consultant organization, organized and funded by a group of Southwest ministers to help low- and moderate-income tenants buy their buildings, and ULS, the Newton Place tenants formed a tenants association and prepared a tenant profile study, operating expense analysis and market study.

"They signed the contract in March of 1983. Then they had to acquire the financing," Malloy said. ULS persuaded the city housing department to lend the tenants $46,780 that must be repaid only if the tenants sell the building within five years. ULS also persuaded the seller to finance $31,600 of the acquisition cost through a 15-year loan at 12 1/2 percent interest.

"It took eight months to arrange the financing," Malloy said. "Then after going to settlement they had to come up with $50,000 for rehabilitation, which has to be done because lenders require that major systems be in working order for the life of the loan. By that they mean plumbing, electricity, roofing."

ULS then asked the District government to lend the tenants the money to rehabilitate their 30-year-old building. The city agreed and gave the tenants a 20-year loan at 3 percent interest. "They were lucky," Malloy said.

The six tenants, all of whom are single, are Washington, Joanne Jenkins, Earlie Hendricks, Maud Patterson, who is 73 and retired, Timothy Harmon, a student at Howard University, and Bettie Perry.

When contract disputes have arisen during the renovation, ULS has been there to help. "They were great . . . . At any hour of the day or night Holly Malloy would come over whenever we needed her," Washington said.

"We could never have done it without them," Washington added. "I feel I've learned so much about buying a home that I could go out and give other people advice on how to do it."